The Science of Cooking Every Question Answered to Perfect Your Cooking

Do Fruits and Vegetables Lose Nutrients as They Age?

Do fruits and vegetables lose

NUTRIENTS AS THEY AGE?

Fresh fruits and vegetables are incredible sources of a wide range of vitamins and minerals.

From the moment a crop is picked, plucked, and vitamin C, which are abundant in citrus fruits, bell

or dug up, the clock starts to tick. A fruit or vegetable peppers, tomatoes, broccoli, and leafy greens.

doesn’t die when it’s harvested, but continues to Vitamins A and E are less fragile, and fiber

take in oxygen and live for days or weeks. HEAT DAMAGE and minerals also survive well for long periods.

However, cut off from the mother plant, SPINACH LOSES OVER The amount of nutrients lost depends on the
vitamins and nutrients in the fruit or vegetable TWO-THIRDS OF ITS type of vegetable, harvesting, distribution,
are used up from its stores, leaving fewer FOLATE IF LEFT AT ROOM storage, and soil conditions—poor soil means
nutrients for us when we finally eat the produce. TEMPERATURE FOR produce has fewer nutrients to start with. The

Several factors affect how quickly nutrients JUST FOUR DAYS. chart below shows the journey of produce

are lost. Heat and light take a toll on many from harvesting to consumption and how

vitamins, especially sunlight-sensitive B vitamins nutrient stores are depleted along the way.

PRODUCE HARVESTING DISTRIBUTION STORAGE

DELICATE Delicate vegetables LOCAL FRIDGE
VEGETABLES can be bruised if Vegetables that are fragile retain Most delicate vegetables should be chilled.
Delicate vegetables, mishandled during freshness and nutrients best if Low temperatures delay chemical reactions in
such as tomatoes, harvesting, depleting transported short distances the cells, protecting fragile nutrients such as
asparagus, and salad nutrient supplies as shortly after harvesting. vitamin C, which is high in many delicate varieties.
leaves, are easily the plant goes into TRANSPORTED PANTRY OR COUNTERTOP
damaged if handled defensive mode. Delicate vegetables are Herbs such as basil suffer if chilled, so they should
roughly, which However, they are vulnerable to crushing during be kept on the countertop with access to sunlight.
speeds the loss more likely to be transportation so are often Unripe tomatoes or avocados can be left on the
of nutrients. harvested by hand harvested before fully ripe. countertop to ripen, but transfer them to the fridge
than by machine. Cuts and bruises cause cells to when ripe if you’re not eating them right away.
break open and leach nutrients.

HARDY Most commercially sold LOCAL FRIDGE
VEGETABLES root vegetables are Local distribution is optimal, Some hardy vegetables, such as carrots,
Root vegetables, harvested by machine, but less important, for hardy parsnips, turnips, and hardier greens such as
such as turnips, which increases the risk vegetables, reducing the risk of kale, are best kept at cold fridge temperatures.
carrots, and parsnips, of damage, causing the damage and helping them to
hold onto vitamins vegetables to lose hold onto their nutrient stores. PANTRY OR COUNTERTOP
and antioxidants for valuable nutrients. The flavor of some hardier vegetables
longer than delicate TRANSPORTED can be affected by the chilly fridge air.
vegetables if Hardy vegetables can be Vegetables such as potatoes, sweet potatoes,
undamaged. scraped if handled roughly onions, and squash can be stored in a cool,
or packed tightly. Vegetables dark, well-ventilated place such as a kitchen
breathe and use up nutrients pantry or cabinet.
after picking, so long distances
deplete nutrient stores.

150 // 151 The Science of Vegetables, Fruits, Nuts, and Seeds

Is it better to eat Making the most of veggies

VEGETABLES RAW? The green tops of vegetables
such as carrots, which we usually
Cooking vegetables is neither inherently bad nor good. discard (see below), are perfectly
edible and add a peppery tang to
Cooking has a mixed effect on nutrients, destroying side dishes and salads.
vitamins and antioxidants in some foods, while increasing
them in others. For example, tomatoes release more of the How to use green vegetable tops
relatively rare antioxidant lycopene and carrots release more Use the green tops of the vegetables
beta-carotene when cooked, but vitamin C (also in tomatoes), below as a flavorful addition to a salad,
several B vitamins, and certain enzymes are destroyed by sautéed alongside other greens, or
heating. To optimize health, it’s important to eat a variety mixed in a soup or broth for extra bite.
of cooked and raw vegetables. The chart below shows how Carrot • Radish • Turnip • Beet
some vegetables retain important nutrients if eaten raw and
others release valuable nutrients when cooked. Alkaloids in
carrot greens have
BETTER RAW BETTER COOKED
a peppery taste.
Broccoli Carrots
Heat damages the Cooked carrots supply Carrot tops contain
enzyme myrosinase a greater number of more vitamin C
that makes anti-cancer heart-protecting than the root.
compounds. carotenoids.
Watercress Spinach CARROT TOPS
As with broccoli, Gentle cooking makes
heat damages the the beta-carotene Should I throw away
important enzyme and iron in spinach
myrosinase. more absorbable. THE GREEN TOPS?
Garlic Cabbage
Heat reduces the Steamed or gently Uncertainty about safety puts many off
amount of the boiled cabbage eating green tops.
health-boosting releases more
enzyme allicin. carotenoids. The green, spindly leaves that adorn the top of
Onions Tomatoes vegetables such as carrots have long been thrown into
These retain more These release more soups and broths, but many of us are uncertain about
antioxidant flavonoids of the antioxidant how edible they are. Recent scares over “poisonous”
and cancer-fighting lycopene after alkaloid chemicals in carrot leaves have put many people
sulfur compounds. cooking. off using these, and a resemblance to poisonous hemlock
Red pepper Asparagus adds to the reluctance to eat the green tops. Alkaloids
These are high in Cooking makes in carrot greens do lend a slightly bitter taste and, in
vitamin C, an unstable cancer-fighting ferulic high enough doses, can be poisonous, but the amounts
vitamin that is acid in asparagus consumed in carrot tops are of little concern. In fact,
damaged in heat. more absorbable. many of the bitter-tasting herbs and salad plants, such
as arugula, owe their pleasant, cutting flavors to the
bitter alkaloids they contain. Treat carrot tops and
other green tops as you would any herb; although, as
with other strong-tasting leaves, avoid overpowering
dishes with them.

Can Leaving Mushrooms in the Sun Really Increase Their Vitamin D Content?

Is it better to peel If peeled, damaged Sweet potato
cells go into defensive nutrient store
OR SCRUB? mode and quickly use
Vegetable skins contain
Many of us have been taught to peel vegetables up nutrient stores. vitamin C and other
to remove dirt and bitter-tasting skin. valuable antioxidants.
Peeling the skin of a
Traditional advice was to peel tough, dirt-ingrained, sweet potato removes
bitter vegetable skins. Today, however, many up to 35 percent of its
vegetables have been bred to be fleshier and vitamin C content.
thinner-skinned, making the skins far more palatable.
In sweet potatoes, iron,
Research shows that the skin contains a host of potassium, and calcium
beneficial nutrients, including antioxidant plant lie just beneath the skin.
chemicals called phytochemicals. The pigments that
give vegetable peel its color are an indicator of the
antioxidants it contains. Vegetables, such as carrots,
whose skins are the same color as the flesh, have
antioxidants spread throughout the flesh, so lose
fewer vitamins if peeled. But in most vegetables,
nutrients are concentrated just beneath the skin.

Peeling vegetables has the benefit of removing
more pesticide residues than scrubbing, but the
amount of pesticides on vegetables is usually tiny
and many of them are destroyed with cooking.
Overall, washing or gently scrubbing is the best
way to retain a vegetable’s goodness.

Can leaving mushrooms in the sun really

INCREASE THEIR VITAMIN D CONTENT?

Fungi have a unique nutritional profile, more akin to that of animals, and can supply important nutrients.

Mushrooms are fungi, and have a unique MUSHROOM
flavor and a meat-like texture. They are
higher in protein than most fruits and SHIITAKE
vegetables, and contain amino acids that give
them an umami, savory flavor. Fungi also OYSTER Effect of
contain vitamins D and B12, normally only BUTTON sunlight
found in animal products. However, ABALONE on mushrooms
mushrooms need UV light to make vitamin
D, and because they are typically grown 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% This table shows the
indoors, they contain little of the “sunshine” INCREASE AFTER 1 HOUR AND 15 MINUTES IN SUNLIGHT amount of vitamin D
vitamin. However, because mushrooms live generated by
after harvesting, putting them out in strong different mushrooms
sunlight for at least 30 minutes will allow their left in sunlight for
skin to create abundant vitamin D (see right). 1 hour and 15
minutes. Chopping
the mushrooms first
maximizes vitamin D
production.

152 // 153 The Science of Vegetables and Fruits

DATA The Process of

How it works STEAMING
Food is positioned above
water rather than in it, and During steaming water is boiled
heat is transferred to the continuously, causing it to vaporize into
steam, which then rises in the pan and
food via steam. transfers heat to the food above.
Best for
Steaming is one of the healthiest Cut the vegetables into
Vegetables; fish steaks and similar-sized pieces to
fillets; boneless chicken cooking methods. As food is not
breasts and small poultry; immersed in water, nutrients that ensure even cooking.
can leach into water are preserved
tender loin and leg meat cuts. and food cooks without the need for Bring the water to a boil. This will ensure that
What to consider fats. This energy-efficient method enough steam is produced for even heat
uses only a small amount of water. distribution. When the water boils, the
If using a steamer with more Water expands enormously when it molecules have enough energy to break
than one tier, place meat or fish turns to steam, and contains energy free as bubbles of steam.
called “latent heat”, released when
on the bottom tier to avoid it strikes the cool food. The diagram
dripping onto food below. opposite demonstrates the steaming
process, showing how food is cooked
14% by the circulating steam.

of broccoli’s vitamin C #2
is lost with steaming,
compared to 54 percent KNOW THE DIFFERENCE

with boiling. Steamed Boiled #1
Food cooked via steam convection. Cooks directly in boiling water.
STEAM CYCLE Heat a small amount
Cooking time: Slightly Cooking time: Direct of water—about 1in
STEAMING USES MINIMAL longer than with boiling. contact with water (2.5cm)—in the bottom
WATER AS RISING STEAM transfers heat quickly, pan of a steamer. When
CONDENSES BACK INTO Flavor and texture: speeding cooking times. heated, the movement
Preserves sweetness and of water molecules
DROPLETS texture of food. Flavor and texture: quickens, energy
May be lost on delicate increases, and the
LATENT HEAT Nutrients: Holds foods. Suits robust foods water temperature
vitamins and minerals such as potatoes. rises to 212°F (100°C).
BUBBLES OF STEAM well.
RELEASE ENERGY, OR Nutrients: Nutrients
HEAT, WHEN THEY TURN can seep into water.
BACK INTO LIQUID WATER

DROPLETS.

The Process of Steaming

Place the vegetables in Water condenses on the underside MAKING ROOM
the steamer basket above of the lid and droplets fall back
the water. When the steam down into the pan. FOOD IN A STEAMER
comes into contact with SHOULD BE LOOSELY
the food, it cools and Cover the pan with PACKED SO THAT STEAM
condenses back into water, a tightly fitting lid CAN CIRCULATE AROUND
releasing vast amounts of to trap the steam in.
latent heat—the energy IT F R E E LY.
contained in the steam. Slightly cooler
steam circulates back Beads of moisture Heat travels
#3 down into the pan. form a film, called into the food
the “film condensate”. from the film
condensate.

Steam rises from the water
at the base of the pan.

Some water evaporates, Steam vapour rises
drawing heat away from towards the food
the food.

#4 Immediately remove the steamer See inside
basket from the pan and take
off the lid to halt cooking and Steam vapour circulates within the pan at a
prevent the vegetables from temperature of 102ºC (216ºF). When the steam
becoming too soft. strikes cool food, beads of condensation create a
“film condensate” of about 91ºC (196ºF) around
the food, shielding the food from direct contact
with the steam. Heat travels into the food from
the film, gradually cooking it.

Key
Water evaporating from the broccoli
Steam
Film of water
Heat traveling from the film

154 // 155 The Science of Vegetables, Fruits, Nuts, and Seeds Why do different-colored

How do I chop an onion PEPPERS TASTE
DIFFERENT?
WITHOUT CRYING?
There’s more to pepper flavor than meets the eye.
Learn how to combat an onion’s self-defense mechanism.
Of all the many colors of pepper, green ones are
Like many vegetables, onions don’t like being eaten. Damage the odd ones out. They are under-ripe peppers, rather
to onion cells results in their releasing an irritating gas called the than a variety in their own right. This means that
lachrymatory factor (see Cell anatomy, below), intended to ward off they contain plenty of chlorophyll, a green pigment
animals and insects. Once this gas reaches the surface of your eyes, that harnesses the power of sunlight to create energy.
it reacts with water on your eyeballs and turns into sulfuric acid, As the pepper reaches maturity, chlorophyll is no
among other irritating chemicals. Your eyes then release tears in longer needed to supply the plant with fuel, so it
an effort to wash away the painful acid. There are a variety of ways breaks down, and, as in an autumn leaf, other
to reduce how much of the irritating gas reaches your eyes (see pigments reveal themselves. The colors and flavors
below), but whichever strategy you use, always use a sharp knife that develop depend on the variety of pepper (see
and try to make as few incisions as possible to cause the least right). The texture softens as the pectin that holds
damage to cells and so minimize the release of irritants. the fruit together weakens, carbohydrates break down
into sugars, and new flavors and aromas develop.

Chilling Precooking Face protection Immersion
Keep onions in the Blanch whole Wear tightly fitting Chop onions in a
fridge or put them onions briefly
in the freezer for before use goggles and a bowl of water or
30 mins before use to deactivate nose plug to help under a running
to slow down the irritant-releasing prevent irritants tap to keep the
release of enzymes. from reaching your irritating mist from
enzymes.
tear ducts. reaching your face.

Irritating sulfur-
containing gas.

Sulfur-containing
amino acid.

Enzymes freed from YELLOW ORANGE
damaged cells react
with amino acids Flavor Flavor
to make irritating gas. Light and fruity-tasting, Rich in brightly colored
beta-carotene, orange
Cell anatomy of a yellow peppers take
raw onion cell their color from lutein. peppers are mild
and sweet.
Slicing or chopping onions damages How to use How to use
onion cells, activating defensive Their natural sweetness
enzymes. These enzymes cause suits eating raw, grilled, Finely slice them and
sulfur molecules in the cell to add raw to salads, chop
split and release an irritating gas or broiled. finely and add to dips, or
called the lachrymatory factor. use as a sweet note in

stir-fries.

Why Do Different-Colored Peppers Taste Different?

200% DID YOU KNOW? You can't ripen peppers at home

Red peppers contain Although many fruits and vegetables can be
twice as much sugar ripened at home, peppers work a bit differently.
Harvesting and ripeness
as green peppers. When it comes to ripening, the fruits of edible plants fall into
two categories: those that ripen after being harvested and
GREEN MAKING PAPRIKA those that ripen only when attached to the plant (see
pp168–169)—and peppers are part of the latter category.
Flavor SWEET OR SLIGHTLY FIERY Because they won't ripen in your fridge or fruit bowl, it's best
Packed with green-tinted RED PEPPERS ARE FIRST to choose perfect, already-ripe peppers when buying.
chlorophyll, green peppers are DRIED AND THEN GROUND
firm and the most aromatic, “Green peppers are
with a fresh “green” smell. TO CREATE PAPRIKA. actually under-ripe
peppers, rather than
How to use
Chop into small pieces and a variety in their
own right.”
use sparingly in stews or
curries to bring added
freshness and vibrancy.

RED PURPLE BROWN

Flavor Flavor Flavor
Red peppers are sweet and Semisweet and A variant of red pepper
juicy, with a deep color due to firm, flavor can vary varieties, brown peppers ripen
pigments called capsanthin depending on the variety. to a rich mahogany brown and

and capsorubin. How to use have a sweet flavor.
How to use Purple peppers often have a How to use
contrasting green interior so
Use to add body and they make visually stunning As heat causes their color to
flavor to sauces and stews, fade, brown peppers are best
or stuff with grains, ground salads or crudités.
served raw.
beef, or feta.

156 // 157 The Science of Vegetables, Fruits, Nuts, and Seeds

How do I roast vegetables

WITHOUT THEM GETTING SOGGY?

The holy grail of oven-cooked vegetables is a flavorful, crispy coat and firm, tender flesh.

Roasted vegetables should be the crowning faster, and dry out less. Between

glory of a dinner, but all too often are limp 110ºF (45ºC) and 150ºF (65ºC), a

and greasy. But with a little scientific 90% protective plant enzyme, pectin
know-how, it’s possible to produce a methylesterase, is permanently
pan of perfectly crisp and firm switched on. This strengthens

vegetables each time. of a carrot is water. pectin “glue” to bind the

Keeping moisture in Potatoes are around vegetable cells, which helps keep
80 percent water. vegetables from losing moisture
Vegetables have a very high water and wilting when they are

content. Losing too much water, which roasted. Very gentle cooking is key.

happens easily in an arid oven, makes Alternatively, cover the roasting pan with

vegetables wrinkle. Partly cooking vegetables by foil in the early stages of cooking as shown below

lightly steaming or gently simmering before crisping so that the vegetables cook first in their own steam

them in the oven helps them to stay firmer, cook before crisping in the hot oven air.

IN PRACTICE ROASTING FIRM, CRISPY VEGETABLES roasting one type of root vegetable or for a mixture of
different vegetables—just make sure that your pan is big
When roasting root vegetables, such as carrots, parsnips, enough to fit them all in without overcrowding.
and potatoes, cut the vegetables into similarly sized pieces
and avoid layering them. This technique can be used for

#1 #2 #3

CUT VEGETABLES EVENLY ARRANGE VEGETABLES LOOSELY COVER BRIEFLY TO TRAP STEAM
Preheat the oven to 400ºF (200ºC). Arrange the vegetables in a large, Cover the roasting pan tightly with a
Cut 21⁄4lb (1kg) mixed root vegetables shallow roasting pan in a single layer. piece of aluminum foil or lid to seal in
and 1 large red onion into evenly sized Sprinkle with aromatic woody herbs, moisture, and place in the preheated
pieces—this will ensure that they cook such as rosemary or thyme. Avoiding oven. Cook for 10–15 minutes, covered,
evenly. Drizzle with 2 tbsp olive oil, overcrowding helps steam escape so they cook first gently in their own
season with salt and freshly ground evenly during the later stages of steam to activate firming enzymes.
black pepper, and toss to coat. cooking, allowing the vegetables Then remove the foil and return the
to crisp and brown. vegetables to the oven.

Does Adding Salt to the Water Cook Vegetables Faster?

How do I cook vegetables to

OPTIMIZE NUTRIENTS?

Cooking has mixed effects on the nutritional value of vegetables.

Of all the ways to cook vegetables, steaming for most vegetables, but
frying and boiling tend to lose most effective for broccoli, asparagus,
nutrients. Water transfers heat rapidly and zucchini, and carrots gain more
to food, but nutrients seep out into carotenoids when boiled rather than
the water. Steaming retains nutrients steamed. Research is also starting to
well, though research also shows that show that sous vide (see pp84–85)
vegetables benefit from different retains most nutrients: the heat is
cooking techniques. For example, carefully controlled and nutrients
lightly griddling is slightly worse than are sealed in the airtight bag.

Key Vitamin C Antioxidants Carotenoids

PERCENTAGE OF NUTRIENTS 140% Cooking for
IN PREPARED BROCCOLI 120% nutrients
100%
80% STEAMED BOILED FRIED This chart shows
60% nutrient levels for
40% cooked versus raw
20% broccoli. Heating
reduces levels of
RAW most nutrients, so
cooler methods are
preferable. However,
some methods
can increase levels
of carotenoids.

Does adding salt to the water cook

VEGETABLES FASTER?

A common belief is that salt raises the temperature of boiling water.

#4 While salt raises the temperature of that fasten the plant cells together—
boiling water a tiny amount (less than pectin and hemicellulose—need to
UNCOVER TO CRISP 34ºF/1ºC; see p144), this is not why dissolve. The acidity, salt level, and
Roast the vegetables, uncovered, for vegetables cook better in salted water. amount of minerals in cooking water
a further 35–40 minutes, or until the can either strengthen or weaken the
vegetables are tender and beginning Salt and other minerals in cooking molecular bonds that keep these
to char around the edges. Remove water have other important effects. glues strong. Salt drives apart the
from the oven and serve warm. Plant cells have rigid walls made pectin strands that give the glue
from tough lignin and cellulose its integrity. The sodium in salt
fibers, in order to keep plants disrupts the connections between
upright. Cooking softens these pectin molecules, so salted
woody fibers to make vegetables vegetables really will cook faster
tender, but before heat from the than unsalted ones.
stove can do this, chemical “glues”

158 // 159 The Science of Vegetables, Fruits, Nuts, and Seeds

What is the secret of the

PERFECT VEGETABLE STIR-FRY?

Making a stir-fry may seem like an easy dinner option, but doing it well requires skill and a lot of heat.

In a professional kitchen, a wok-wielding chef manipulates break apart in the searing heat of the pan, which turn into
food at a ferocious speed. This is because stir-frying success more tasty molecules that combine with those created by
is all about cooking food quickly, which requires high the Maillard process to create smoky stir-fry flavors. Pieces
temperatures and fast-moving ingredients. of food should be thinly sliced and evenly cut so that the
outside doesn’t burn before the center cooks and softens.
Feeling the heat
With such high temperatures, it is important to keep the
To make a perfect stir-fry, you need the wok to be as hot food moving by constantly tossing or stirring it so it cooks
as possible and the oil smoking. When food strikes a very evenly. Keep the burner turned up high and add fresh
hot pan, water on its surface evaporates almost instantly and ingredients one at a time so the pan’s surface stays hot. Even
Maillard browning (see pp16–17) starts. Cooking oil molecules when airborne, the food continues to cook in the rising steam.

IN PRACTICE MAKING A VEGETABLE STIR-FRY sided wok are important for keeping everything in the pan.
Don’t let food linger at the sides of the wok as they are
For an authentic smoky stir-fry flavor, your stove needs much cooler than the center, and will cook food too slowly.
to be on the highest heat setting, and the oil should be
smoking before any food is added. A spatula and a high-

#1 #2 #3

CHOP INTO SMALL PIECES BRING TO THE SMOKE POINT DEVELOP AND SPREAD FLAVORS
Chop 1lb 5oz (600g) of mixed Heat a large wok over high heat Add the vegetables to the wok in small
vegetables (such as peppers, carrots, until a sprinkling of water evaporates batches, in the order of how long they
mushrooms, broccoli, and baby corn) within 2 seconds of contact with the take to cook—harder vegetables first.
into thin strips or pieces. Grate a wok. Add 1 tbsp peanut oil, and swirl Once all the vegetables are just
thumb-size piece of ginger, and thinly the pan to coat its surface. When the cooked (they should still have a little
slice a piece of lemongrass and two oil starts to smoke, add the garlic, bite), add the prepared sauce to the
garlic cloves. Whisk 6 tbsp of soy ginger, and lemongrass, and stir-fry sides of the pan and stir-fry for another
sauce with 1 tbsp of sugar and 2 tsp them for 1–2 minutes to allow flavors minute. Serve immediately over
of sesame oil. to develop and infuse the oil. cooked rice or noodles.

“ High temperatures can
damage a nonstick wok. If using
nonstick, fry the garlic and ginger
in oil over medium heat, then
”add the vegetables and sauce,
and steam everything under
a tight-fitting lid.

In focus 160 // 161 The Science of Vegetables, Fruits, Nuts, and Seeds

POTATOES

The most popular vegetable globally, more potatoes are grown KNOW YOUR POTATOES
than onions, tomatoes, zucchini, and beans combined.
Some potatoes are more starchy compared
The humble potato is a surprisingly versatile (called anthocyanins), which may help to to others. Mealy potatoes have cells densely
and nutritious ingredient. The vegetable itself lower the risk of cancer and heart disease. packed with starch granules that burst open
is the plant’s underground energy stockpile The number of potato varieties is bewildering, during cooking, creating a softer texture.
(the tuber) that provides fuel during the winter but from a cook’s perspective, they group into Waxy potatoes contain less starch and
months. Rich in starch, potatoes have fewer “mealy” (floury) or “waxy” (see right), based on stronger cells that give a firmer texture.
calories than pasta and rice, and are a good texture and consistency when cooked, and it is
source of fiber, minerals, and vitamins— important to choose the right type for a dish. MEALY/FLOURY
especially potassium, vitamin C, and B
vitamins. Colored potatoes, such as purple and New potatoes are not a specific type of Maris Piper
blue varieties, also contain additional pigments potato, but rather immature potatoes that are A high-starch mealy
picked earlier in the season. potato, it is ideal for
roasting and fries. The
Potato skin SCIENCE STARCH: HIGH starch cells rupture
Fiber-rich, this comprises a FIBER: easily, forming a furry
PACKED WITH STARCH coat that can be
layer called the periderm, GRANULES, THE CELLS OF 2.4G PER 100G browned into a
which replenishes itself and MEALY POTATOES R UPTURE tasty crust.
STARCH: HIGH
protects the potato. WHEN THEY SWELL FIBER: King Edward
DURING COOKING. This creamy potato
1.3G PER 100G with a characteristic
COOKING Fluffy red “blush” has a high
mashed STARCH: MEDIUM starch content and a
EASY TO CRUSH, THESE potato FIBER: floury texture when
ARE IDEAL FOR MASHING, M E A LY cooked, ideal for mashing.
ADDING TO SOUPS, AND 2.7G PER 100G When fried in oil, it
has a malty aroma and
CAN BE ROASTED a crispy edge.
AND FRIED.
Yukon Gold
With a fluffy texture
and a medium starch
content, these buttery-
yellow potatoes work
well mashed or baked.
They retain their color
even after cooking.

STARCH: HIGH Rooster
FIBER: Combining high starch
with smooth, yellow
1.6G PER 100G flesh, this is a versatile
potato that works well
baked, roasted,
mashed, and boiled.

Color variations WAXY
The starchy flesh of
potatoes is commonly STARCH: LOW Charlotte
a yellow hue. Potatoes FIBER: This smooth-fleshed,
with red and purple- waxy potato has a
colored pigments 1.0G PER 100G relatively low number
have a higher of starch granules and
antioxidant quota. STARCH: MEDIUM holds its shape during
Blemishes and spots FIBER: cooking, making the
Small, dark spots are potatoes ideal for
known as lenticels, tiny 1.3G PER 100G salads and gratins.
orifices that enable the
tuber to breathe. Moisture STARCH: MEDIUM Desirée
can make these swell, so FIBER: This popular red variety
potatoes should be kept has creamy flesh and a
in a dry place. 1.17G PER 100G firm, waxy texture that
holds its shape well for
Firm texture. STARCH: LOW boiling or wedges.
FIBER: Unlike very hard waxy
SWEET SCIENCE COOKING potatoes, it can also be
POTATOES 1.2G PER 100G used for mashing.
WAXY POTATOES HAVE A THEIR ABILITY TO HOLD In Focus: Potatoes
SWEET POTATOES ARE SMALLER AMOUNT OF THEIR SHAPE MEANS WAXY Purple Majesty
FROM AN ENTIRELY POTATOES ARE IDEAL FOR Delicate and nutty
FIRM AMYLOSE STARCH, SALADS, ROASTS, BOILING, in flavor, these
DIFFERENT PLANT FAMILY LESS LIKELY TO BURST waxy potatoes have
FROM MOST POTATOES, AND STEAMING. succulent, firm, purple
OPEN CELLS WITH flesh that is especially
AND ARE ONLY A DISTANT COOKING. suited for boiling and
RELATION. steaming.

Anya
These are firm in
texture and have a
slightly nutty flavor,
making them ideal for
salads or roasting with
a pan of vegetables.

WAXY

“ For dense, creamy pomme
purée–style mashed potatoes,
use waxy potatoes such as red
potatoes. A purée needs a lot of
blending, and starchy potatoes
will release too much starch
”and become gluey.

How Do I Make Fluffy Mashed Potatoes?

How do I make

FLUFFY MASHED POTATOES?

Unlike purées that can be whipped into an ever-smoother blend, potatoes require more careful handling.

When mashed, potatoes are at risk of turning gluey and elastic-like amalgam, and what was a light and airy mash
rubbery if overworked, so they should be treated with the transforms into a sticky paste. When mashed potatoes start
same care that you would give a meringue or pastry dough. to cool, the starches lock together more tightly, known as
retrogradation, firming them up further and making them
For fluffy mashed potatoes, use mealy, or starchy, hard, so mashed potatoes are best served right after cooking.
potatoes, such as Idaho or Russet,which are full
of water-absorbent starch granules. When cooked, the Adding water can cause potato starches to overgelatinize.
starches swell and soften, meaning that the potatoes’ cells Instead add fats, such as cream, butter, or oil, to lubricate
easily separate under the force of a fork or masher (see starchy cells gently. When cooling, fat hampers retrogradation,
below). Taken too far, however, the starch becomes an so the potatoes can be chilled and reheated another day.

IN PRACTICE MAKING SMOOTH MASHED POTATOES indicated. If you slice them too thinly, this damages a lot of
cells, causing them to leak calcium, which strengthens the
The technique below uses a potato masher for a smooth pectin glue binding the cells, making mashing more difficult.
mash. You can also use a potato ricer, which removes lumps
without overworking the mixture. Chop the potatoes as

#1 #2 #3

CHOP INTO EVEN SIZES MASH TO RELEASE STARCH ENHANCE TEXTURE WITH FAT
Cut the potatoes into similarly sized Start to mash the potatoes to separate After the initial mash, you can add
pieces to ensure even cooking. Put the and rupture the cells so they release fat such as butter, cream, or oil. This
cut potatoes into a pan of cold, rather the gelatinized starch, forming a helps to thin out the increasingly
than boiling, water. This helps even smooth, sticky gel that binds the mash. starchy potato to keep the mash from
out cooking and prevents the edges Do an initial mash without adding fat becoming too gluey. Mash just until
from softening excessively and because the lubrication from the fat the potatoes are smooth and fluffy;
disintegrating. Cook until soft-boiled, will make mashing difficult. overmashing will cause the swollen
and then rinse to remove excess starch. starch granules to knit together too
tightly and create a rubbery texture.

164 // 165 The Science of Vegetables, Fruits, Nuts, and Seeds

DATA The Process of Metal walls reflect the
microwaves so that
How it works MICROWAVING they bounce around
Microwaves agitate water and the oven.
By heating water and fat molecules
fat molecules in the food, within food, rather than heating the
causing them to heat up and surrounding air, microwaving is a
quick and efficient cooking method.
cook the food.
Best for Microwaves have a strange effect on water
and fat molecules: they cause them to line
Vegetables, popcorn, nuts, and up, like a sergeant calling them to attention.
scrambled eggs; melting butter Changing the direction of the microwaves
and chocolate; reheating food. spins and agitates water and (to a lesser
extent) fat molecules enough to heat them
What to consider up (called dielectric heating) and so cook
Small, dry pieces of food may the food. Microwave cooking retains
take longer to cook because of nutrients extremely well because of the
the lack of moisture. Cooking quick cooking time and little extra water
two portions together can take for the nutrients to leak into.

twice as long because the MYTH BUSTER
energy is absorbed as food cooks.
Myth
UNEVEN THAW MICROWAVE OVENS COOK FOOD FROM

WATER MOLECULES IN ICE THE INSIDE OUT.
ARE LESS MOBILE THAN IN
LIQUID, SO IT IS DIFFICULT Truth
TO DEFROST FOOD EVENLY
This is only a half-truth. Microwaves
IN A MICROWAVE. penetrate food farther than direct heat—
about 1in (2cm)—and heat up water as
BROWNING they go, but will not reach the core of the

MICROWAVES DON’T BROWN food (unless it is a very small piece).
FOOD WELL: ONCE THE

SURFACE HAS DRIED, THE
MICROWAVE HEATING

SLOWS DUE TO LACK OF
MOISTURE.

ELECTROMAGNETIC See inside Key
Blocked microwaves
MICROWAVES AREN’T The metal sheet inside the glass Escaping light waves
RADIOACTIVE; THEY ARE A door has perforated holes about
TYPE OF ELECTROMAGNETIC 1mm (1⁄25in) in diameter. The Perforations
wavelength of microwaves is in metal sheet.
RADIATION, LIKE LIGHT typically about 12cm (5in), so
AND RADIO they cannot escape through
WAVES. the gaps, whereas visible light,
which is 400–700 nanometres
in wavelength, can escape, which
allows you to see inside the oven.

The Process of Microwaving

STIRRER SCATTERS THE WAVE GUIDE CHANNELS MAGNETRON CREATES Fan keeps the
MICROWAVES THE MICROWAVES MICROWAVES magnetron cool.
The motion of the stirrer, This carries and directs This is a type of electron
a spinning metal blade, the microwaves from the tube, (or “cathode ray tube”)
distributes the microwaves magnetron through to like those in an old-fashioned
around the oven, ensuring the cooking chamber. TV, that generates the
that they constantly change high-energy microwaves
direction, so that food cooks #4 that will be fired into the
as evenly as possible. food to heat it.

#5 #3

Magnetron is the source
of the microwaves.

Partially cover with #2 SET THE TIME
plastic wrap or a lid to AND POWER
stop steam from escaping. Since food
Microwaves deflect off absorbs some of
metal and can pass through the microwave
glass and plastic, but are energy as it
absorbed by food and water. heats, cooking
two portions of
food takes
longer than one.
For instance,
you may need 5
minutes to cook
one potato, but
9 minutes to
cook two.

#1 Opening the door cuts off
power to the magnetron.
PLACE FOOD ON TURNTABLE Transformer raises the
All food must be kept on the voltage of the electricity
rotating plate so no part is entering the magnetron
left in a “cold spot.” The to 2,000–3,000 volts.
bouncing microwaves
concentrate their energies Rotating See inside
in some regions, but cancel molecules in Water molecules i(nHt2hOe)mhaidvdelea negative
each other out in others. electrical charge and positive
Food should therefore always the raw charges at the tips. When electromagnetic
be stirred and moved vegetables. microwaves meet water in food, the molecules
midway through cooking. spin to align with the radiation. In a microwave
Key oven, the microwaves constantly change direction,
Water molecule rotating the molecules so much that they heat
Movement of water molecule up and cook the food. To a smaller extent, fat
Electromagnetic microwave radiation and sugar molecules behave in a similar way.

166 // 167 The Science of Vegetables, Fruits, Nuts, and Seeds

How does lemon juice keep Is juicing a good substitute for

SLICED FRUIT FROM WHOLE FRUITS AND
TURNING BROWN? VEGETABLES?

Most fruit has a protective browning reaction. One juice holds much of our daily fruit-and-veggie quota.

Fruit has a host of enzymes and chemicals designed to Fruits and vegetables owe their firm structure to the
deter pests, parasites, and bacterial invaders by turning its rigid scaffolding that surrounds each of the trillions of cells
exposed flesh a mushy brown (see below). This enzymatic within them. These tough cell walls are strengthened by
browning can be slowed, but is hard to stop completely indigestible cellulose and lignin. Advocates of juicing, or
without cooking the food (heating to 194ºF/90ºC or above blending, produce suggest that breaking down fruits and
permanently deactivates the browning enzyme). Otherwise, vegetables helps the released nutrients to reach the
the most effective way to halt browning is to drizzle lemon bloodstream more quickly. However, conventional juicers
juice over sliced fruit or vegetables because acids also lose precious fiber and nutrients in the discarded pulp.
disable the browning enzyme. Other, less effective methods Blenders retain all of the pulp, but nutrients quickly degrade
include keeping cut fruit or vegetables under water or in because protective enzymes start to brown produce as soon
syrup to keep oxygen out, and chilling or freezing to slow as it is damaged (see opposite). While juicers may not be an
down the cascade of defensive chemical reactions. ideal replacement for whole fruits and vegetables, they are a
highly nutritious accompaniment to a balanced diet.
How enzymes Phenols
discolor fruit escape when WHOLE FRUITS AND VEGETABLES
cells are cut. Eating whole fruits and vegetables
Inside a fruit cell is a ensures that fiber is retained and, if
storage chamber called produce is eaten right away, few
a vacuole. This contains nutrients are lost. Vegetables and
substances called phenols, fruits can leach nutrients during
which spill out when a cooking, although some methods
cell bursts. An enzyme, enhance nutrients (see p157).
also released from the
damaged cell, turns BLENDER
colorless phenols into High-powered blenders rapidly
rusty-brown pigments. pulverize and purée fruits,
vegetables, and seeds, which
An enzyme called THE PROCESS exposes the pulp to air. Added
PPO acts on blades can also break up nuts.
The pulp is puréed into the
phenols, causing juice, so retaining the fiber.
them to discolor into
JUICER
brown pigments. The sharp blades of a
Once sliced, juicer spin at up to 15,000
texture starts times a second, breaking
to soften and down woody fiber and
flavor is lost. shredding cells. The
fibrous pulp is caught
in a mesh, and the liquid
contents drain out.

SLICED APPLE

Is Juicing a Good Substitute for Whole Fruits and Vegetables?

EFFECT ON NUTRIENTS THE RESULT

100% ALL THE GOODNESS MANY VALUABLE WHAT TO CONSIDER
vitamins Whole fruits and ANTIOXIDANTS When eaten whole, fruits
retained vegetables offer ARE LOCATED IN and vegetables are broken
the best nutritional THE PITH AND PEEL down naturally, first by
value as vitamins OF FRUITS AND chewing in the mouth,
aren’t degraded VEGETABLES. and then at a molecular
before eating. level by digestive enzymes
FLAVOR in the stomach, releasing
WHOLE 100% EVOLVES IN their nutrients. It takes
fiber THE MOUTH longer to eat whole fruits
retained AS PRODUCE and vegetables, so you’re
IS CHEWED. likely to consume fewer
than the quantity
contained in one juicing.

90-100% NUTRIENTS KEPT JUICE SHOULD BE DRUNK WHAT TO CONSIDER
vitamins Most of the fiber QUICKLY AS ENZYMES It’s easy to consume a
retained is maintained. As RAPIDLY DULL FLAVOR large number of fruits and
with a juicer, some vegetables. Blenders retain
vitamins are lost ONCE PRODUCE HAS BEEN fiber and vitamins, but, as
when the produce BROKEN DOWN. with juicers, protective
is broken down. enzymes are triggered
ACID IN CITRUS when released from the
BLENDER 90% JUICES CAN BE confines of the fruit and
exposed to air, and these
or more fiber DAMAGING start to break down
retained TO TOOTH nutrients. Vitamin C and
ENAMEL. other delicate antioxidants
degrade quickly when
left sitting in a glass.

70-90% FIBER IS LOST WITHOUT FIBER AND WHAT TO CONSIDER
vitamins Juice from a juicer BULK, JUICES CAN BE As with blending, a lot of
retained contains little or no CONCENTRATED IN SUGAR: produce can be quickly
fiber as this is lost AN 8FL OZ (250ML) GLASS consumed, but many
with the pulp, antioxidants from the
along with many CAN CONTAIN OVER pith and peel are lost.
antioxidants. 5 TSP SUGAR. Centrifugal (spinning)
juicers froth liquid with
JUICER 0.1% NINE MEDIUM-SIZE air, accelerating enzymatic
fiber CARROTS CREATE breakdown reactions (see
retained opposite). Juice can offer
ONE GLASS OF an intensity of flavor that
JUICE. surpasses whole fruit as
flavors are released
immediately, instead of
evolving on the tongue.

168 // 169 The Science of Vegetables, Fruits, Nuts, and Seeds

How do bananas help Green chlorophyll
in unripe bananas
RIPEN OTHER FRUIT? is destroyed as the
fruit ripens,
Bananas hasten the ripening of other fruits in your fruit bowl; understanding revealing other
the plant’s survival tactics helps explain bananas’ ripening powers. colorful pigments.

Many plants develop their fruit in CLIMACTERIC These fruits are ripened by
synchrony, maximizing their chances of FRUITS ethylene, so you can hasten
attracting animals, which disperse plant seeds ripening by placing them near a
over a wide area. Ripening is coordinated NON-CLIMACTERIC ripe banana (see right).
by a chemical signal: ethylene gas, which FRUITS
plants release when the climate is right or if Bananas • Melons • Guavas •
the fruit is damaged. Ripening softens fruit, Mangoes • Papayas • Passion fruits
releasing flavor molecules and increasing • Durians • Kiwis • Figs • Apricots •
sugar levels (see opposite). As bananas Peaches • Plums • Apples • Pears
produce large quantities of ethylene, they • Avocados • Tomatoes
can be used to ripen climacteric fruits
(fruits that ripen off the plant) at home. Fruits that ripen only when they are
on the plant and so cannot be
“Ripening is ripened at home.
triggered by a chemical
Oranges • Grapefruit • Lemons • Limes
signal—a gas called • Pineapples • Dragon fruits • Lychees
ethylene.” • Peppers • Grapes • Cherries •
Pomegranates • Strawberries •
Raspberries • Blackberries •
Blueberries

36% How do you use bananas Unripe, green
at different stages bananas are packed
of the carbohydrates with nutritious fiber.
in a green banana are OF RIPENESS?
sugar; 83% in a yellow UNDERRIPE
Hard green bananas quickly become speckled
banana. and soft, but you can still use them in cooking. Underripe bananas are green
or green and yellow, with thick
GOING BANANAS You may be tempted to buy already-ripe bananas for a skin and firm flesh. The starches
quick snack fix, but if you opt for green bananas instead, have not yet begun to break down
OVER 110 MILLION TONS OF you’re providing yourself with a whole host of culinary into sugars, and the cell walls are
BANANAS ARE GROWN AND options. As bananas ripen from green to yellow to brown, still tough and fibrous.
SOLD EVERY YEAR. INDIA IS they become softer, more flavorful, and sweeter.
Underripe bananas are packed with fiber and pectin- Best for
THE WORLD’S LARGEST strengthened cells, and add structure and mild flavor Slicing over oatmeal, making green
PRODUCER. to dishes. Soft, sweet, ripe bananas lend themselves to banana fries, thickening smoothies,
eating raw or using in baking (see right). Bananas ripen or using as an alternative to plantain.
quickly, so whichever level of ripeness you prefer, use
them swiftly or freeze them to halt the ripening process.

How Do You Use Bananas at Different Stages of Ripeness?

Starch granules Sugar molecules Cell anatomy of
a ripe banana
Cell anatomy of
an unripe banana Ripening bananas produce ethylene
(see opposite), which prompts
Unripe banana cells contain
a high quantity of starch enzymes in fruit cells to convert
starches into sugars, reduce chlorophyll
granules and a low amount production, release fragrant molecules,
of sugar. The starches will
and soften their cell walls.
break down into sugar as
the fruit ripens.

Once ripe, Ripe, speckled
ethylene levels bananas release
start to fall.
less ethylene.

Overripe, brown
bananas release
little to no ethylene.
Bananas with large brown
patches are overripe and
should be used quickly or
frozen.

RIPE VERY RIPE OVERRIPE

Ripe bananas are slightly firm, with Very ripe bananas are soft-textured with Overripe bananas are mushy-textured with
creamy flesh and yellow, sometimes heavily speckled, bright yellow skin. Ethylene brown-mottled, deep yellow skin. Rich with
speckled skin. Flavor molecules and production is now past its peak, so the banana natural sugars, they have a very strong flavor.
sugars have developed sweet, fruity will ripen other fruits slowly. They are They won’t ripen other fruits, but use quickly
notes, and they can still withstand flavorful and packed with sugar. or freeze for later use.
cooking. Bruising hastens ripening.
Best for Best for
Best for Baking in cakes and muffins, caramelizing, Baking in cakes and muffins, mashing into pancake
Eating raw, blending into smoothies, adding flavor and sweetness to smoothies, or batter, sweetening smoothies or oatmeal, or
baking in tarts or pies, or slicing into freezing and blending into a simple “ice cream.” flavoring milkshakes.
custard or caramel sauce.

170 // 171 The Science of Vegetables, Fruits, Nuts, and Seeds

Can I cook soft fruit from FRESH

FROZEN? FROZEN Cell structure in a
fresh blueberry
Frozen fruit is convenient, but some DEFROSTED
care is needed when cooking with it. Cell walls are undamaged
in fresh fruit, and the
Prefrozen soft fruits open the oven door fruit’s firm scaffolding
to the possibility of year-round blueberry is fully intact.
muffins, and are a great alternative to fresh
fruit in desserts, as long as you understand Ice crystals in a
how subzero temperatures change soft fruit. frozen blueberry
Like most frozen foods, fruits suffer damage
when frozen because spiky ice crystals form Spiky ice crystals form
inside them (see right). Commercially inside the fruit as it sets in
frozen fruits are rapidly “flash frozen” to at the freezer, damaging the
least –4ºF (–20ºC) to limit how large these fruit’s internal structure.
ice crystals grow, but because fruits contain
so much water—typically over 80 percent—
they lose much of their natural bite.

Because of this damage, thawed soft fruit
will have a softer, more mushy consistency
than fresh and will leak an unsightly
puddle of fruit juice. This colored fluid
isn’t added liquid but the natural fruit juice
escaping. For making smoothies, juices,
and flavored milks, this is not a problem,
but for baking, the liquid can cause ugly
splotches. Follow the tips below right to
cook successfully with frozen soft fruit.

“Commercially frozen Cooking tips Cell damage in a
fruit is ‘flash frozen’ to thawed blueberry
limit ice crystal damage.” · To avoid having too much fruit juice leak out during
cooking, don't thaw fruit before cooking with it—it As the ice melts, the
FRESH ONLY will weigh the same as when fresh, so it can be used microscopic puncture
in the same amounts. holes in the cell walls are
FROZEN FRUIT ISN’T unplugged, causing the juice
SUITABLE FOR OPEN TARTS, · Cook frozen fruit for slightly longer to allow inside the cells to leak out.
for the extra energy needed to thaw the fruit.
FOR WHICH IT IS
IMPORTANT FOR FRUIT · If frozen berries have started to thaw before they
SLICES TO RETAIN THEIR are put in a baking mix, dust them with sugar or
flour to soak up the juices.
SHAPE AND BITE.
· The chilling process can cause the fruit to turn
brown. Sugar and ascorbic acid can help slow the
fruit’s browning enzymes, so it can be worth
buying frozen fruit with these ingredients, bearing
in mind that they give the dish a slightly sweeter
and tarter flavor.

How Can I Cook Fruit Without It Turning Mushy?

How can I cook fruit without it

TURNING MUSHY?

Fruit is all too often neglected by cooks, but this naturally sweet ingredient can deliver
a host of fresh flavors and dimensions to sweet and savory dishes.

To cook fruit successfully, pick the right variety acid (see below) and sugar. Sugar pulls water away

(see below) and use when appropriately ripe. from pectin, so it dissolves more slowly.

What happens during ripening Poaching fruit with acids, such as lemon

As fruit ripens, natural enzymes go to work, PECTIN BOOST juice or wine, and a sweet syrup will also
keep them firm. For purées and sauces,

breaking down starches into sweet sugars, IF YOU ARE COOKING IN A cook first without sugar to quickly soften
releasing fruity aromas, destroying green HARD-WATER AREA, THE fruit, then sweeten later. If baking at lower
pigments, and weakening the strong pectin ADDED CALCIUM IN THE temperatures, blanch fruit first on high
chemical “glue” that holds the cell walls WATER WILL STRENGTHEN heat for a couple of minutes to disable
PECTIN, KEEPING FRUIT

together. Cooking breaks down pectin further, FIRM. a pectin-strengthening enzyme, pectin

so if you want fruit to hold its shape and texture, methylesterase: it can stop fruit from softening

cook with it when it is ripe enough to taste sweet because it’s permanently active at less than 149ºF

but is still firm. Pectin is strengthened by cooking with (65ºC), and only deactivated at 180ºF (82ºC).

CHOOSING APPLES EATERS

Some apple varieties hold up to cooking better than others. Pectin Air spaces between
glue is bound with calcium and strengthened by acid. Low-acidity cells are larger.
eating apples are less tart, but don’t withstand cooking well.

COOKERS

Pectin bonds

Cell walls There are
are tightly fewer pectin
joined. bonds along
Pectin in Pectin in
cell walls. eating apples

cooking apples

Acidic, tart-tasting varieties, such as COOKING EATING Eating-apple cells have less pectin than
Granny Smith, have cells bound together APPLE APPLE cooking apples and are bound together more
by more pectin than eating apples,
which helps to strengthen the cell walls. loosely. Their low acidity further weakens
the pectin so the cell walls are less stable.

172 // 173 The Science of Vegetables, Fruits, Nuts, and Seeds

Why are olives MAKING OLIVES EDIBLE

BRINED? METHOD TIME R E S U LT

When fresh, all but the ripest olives INDUSTRIAL-SCALE SOAKING 1–2 This produces a firm,
are hard to bite and even harder on HOURS easily sliced olive,
Unripe olives are soaked in huge tanks in but the taste can be
the taste buds. “lye,” or caustic soda. This breaks the stringent bland, with a slight
oleuropein molecules apart; the tough, waxy chemical aftertaste.
Fresh olives are extremely bitter and barely skin softens, the cell walls fracture, and the Often canned and used
edible thanks to a bitter substance called “pectin” glue that binds cells dissolves. as pizza toppings.
oleuropein. To soften them and remove
oleuropein, they need to be soaked, cured, TRADITIONAL SOAKING 1–2 This removes some, but
and/or fermented. Repeated dousing with WEEKS not all, of the bitterness,
plain water will wash away enough Washing 6 PLUS so washed olives may be
oleuropein to make olives edible, although Olives are washed repeatedly over a couple WEEKS subsequently brined.
traditionally olives are left in salt to shrivel of weeks in fresh plain water to remove as Olives may be wrinkled
or ferment for at least six weeks (see right). much oleuropein as possible. (if just cured in salt), and
have a concentrated
Food producers can now make olives Salting flavor, enhanced by oils,
edible within one to two hours (see right) Olives are fermented in brine or cured herbs, and spices.
using a technique based on one used during in salt for at least six weeks. In this form of
Roman times, which involved adding wood pickling, taste and aroma evolve as salt-resistant
ash to water to break apart oleuropein. microbes acidify to form new flavor molecules.

“A substance called oleuropein accounts
for the bitter taste of fresh olives.”

Are black olives really

DYED?

Olives start life a cheery green and slowly ripen into a dark purplish black.

As a fresh olive fully ripens, it becomes they have been soaked to the core. The olives are

wrinkled and develops a strong, earthy 95% then “manipulated” into turning black: air is
flavor. Something of an acquired taste, the bubbled through the soaking water to
mass-produced “black olives” sold in cans oxidize and darken surface pigments called

or jars are often not the potent fruit that of olives grown in phenols, and then an iron salt, called ferrous
have been given time to ripen, but are the the United States are gluconate, is added to fix the color change
less flavorful green olives masquerading California olives, grown to an inky black. These olives have the
as their more mature counterparts. appearance of a ripe black olive, but the
over 27,000 firm and smooth consistency of a green one.
California “ripe black olives” take the acres. A favorite topping for pizzas, they are easily
lye-washing process described above a step

further by repeatedly washing green olives until sliced and are not bitter.

“ Cooks in Roman times realized
that mixing wood ash into the
water that olives were soaking in
quickly de-bittered the olives.
The ash turned the water alkaline,
breaking apart the astringent
”oleuropein molecules.

In focus 174 // 175 The Science of Vegetables, Fruits, Nuts, and Seeds

NUTS

Densely packed with essential nutrients, nuts add crunch KNOW YOUR NUTS
and creaminess to a wide variety of dishes.
Nuts can be shelled, unshelled, and
Nuts have evocative aromas, enhancing the 800 calories per 43/4oz (135g). This means blanched to remove the skin. Pale flesh
taste of other ingredients and lifting both they are best consumed in moderation. Many indicates freshness—areas of darkness
sweet and savory dishes. people consider nuts a “superfood” because, suggest that oils have started to oxidize. All
as well as protein, they contain a spectrum of nuts contain fat and are a source of protein,
These little nuggets of nutrition and flavor important minerals and vitamins. They also but some have higher levels than others.
are loaded with oils and protein—a plant pours have high omega-3 and unsaturated fat levels.
its resources into its nuts and seeds to give the NUTS
next generation the best chance of survival— Most nuts can be eaten raw, but toasting or
and have sustained our species for at least roasting them adds an extra level of flavor Cashews
12,000 years. Weight for weight they have more and texture. Watch them carefully while Cashews have a
calories than most other ingredients (except they cook, as, due to their size, it is easy smooth, buttery texture.
cooking oil and butter), averaging about to overcook them. An unusally high starch
content makes them
SCIENCE COOKING FAT: LOW useful for thickening
PROTEIN: HIGH sauces and soups.
CRUSHING SOFT-TEXTURED CRUSH CASHEWS AND
NUTS BREAKS OPEN THE BRAZIL NUTS IN A FAT: LOW Pistachios
TINY PACKETS OF OIL PROTEIN: HIGH Sweet and meaty,
THAT ARE LOADED IN MORTAR AND PESTLE this member of the
THE CELLS. TO FORM NUT BUTTERS FAT: LOW cashew family is high
PROTEIN: HIGH in protein and fiber, so
AND PASTES. it bulks out sweet and
savory dishes. Chop
BUTTERS them and sprinkle them
over food to add color.
Almond butter
Almonds
Sweet almond’s skin is
nutrient dense, notably
containing flavonoids,
which are good for heart
health. With a malleable
texture, they can be
eaten whole, sliced,
or ground into flour.

NOT A SCIENCE Bitter skins FAT: MEDIUM Hazelnuts
REAL NUT The papery skin on many nuts PROTEIN: MEDIUM Sweet, crunchy, and
HEAT CONVERTS SUGARS is packed with antioxidants, but full of healthy oils,
ACTUALLY FROM A AND PROTEINS INTO MORE often has a bitter, off-putting FAT: MEDIUM hazelnuts provide
PL A NT I N TH E PE A FAM I LY, taste. When lightly roasted, the PROTEIN: MEDIUM texture and body to
FLAVORFUL MOLECULES skin usually peels off easily. dishes—try them as
PEANUTS AREN’T TRUE THROUGH MAILLARD FAT: MEDIUM a topping on salads.
NUTS, BUT LEGUMES. BROWNING (P16). Pistachios PROTEIN: MEDIUM
Walnuts
Structure of nuts FAT: HIGH These large, meaty In Focus: Nuts
Nuts are essentially hard, PROTEIN: LOW nuts, high in bitter-
single-seeded fruits that tasting tannins, balance
grow and ripen encased FAT: HIGH flavor well with sweeter
within a hard shell. PROTEIN: LOW ingredients. They have
been described as the
Roasted healthiest nut due to
cashew nuts their antioxidant levels.

TOASTING Brazil nuts
OR ROASTING These large nuts have
a chewy, soft texture,
COOKING making them ideal for
creating nut butters or
TOAST OR ROAST NUTS milks. This is because
TO RELEASE COMPLEX, the oil within the cells
BUTTERY FLAVORS AND form globules like the
fats in milk.
GIVE THEM A MORE
CRISPY TEXTURE. Pecans
With a sweet, rich
flavor, pecans add
crunch to desserts and
baked goods. They
contain the same
healthy fats found in
olives and avocados,
and vitamin B3.

Macadamia
Macadamias have
a soft texture and a
creamy flavor, so they
are ideal for sweet
dishes or baked goods.
Although high in
fat, much of this is
monounsaturated fat,
which can help to
lower cholesterol.

176 // 177 The Science of Vegetables, Fruits, Nuts, and Seeds

How can I enjoy the

FRESHEST NUTS?

Nuts owe much of their unique character to the oils they contain, which also affect their longevity.

The healthful, aromatic oils concealed within open so you can check its quality. The flesh should look

nuts are unsaturated, making them good for our pale—any darkening or shininess suggests that the

arteries but bad for storing. These delicate fat nut has been damaged, meaning that oil has

molecules are easily broken apart by light, started seeping from the cells and the nut

heat, and moisture, and react readily with DRY NUTS will have already begun to turn stale. In

oxygen, fragmenting and degrading into THE SHELL AND SKIN OF the same way, high temperatures also cause
acidic and offensive-tasting molecules. NUTS ARE DESIGNED TO the sealed oil packages within the cells to

What should I look for? KEEP WATER OUT, HELPING break open, hastening rancidity. When
TO PRESERVE NUTS AFTER the shell and skin are intact, these
THEY HAVE BEEN
You should aim to buy and use nuts that are HARVESTED. protective casings preserve the nut for
no more than six months old—use the tips below months after it has fallen from the plant.

to ensure you enjoy the very freshest nuts. If you Finally, ensure you store nuts carefully to maintain

buy nuts from a market, ask the seller to break a nut freshness (see box, below).

Protective Buy vacuum-packed Buy in season
outer casings
or shells protect If fresh nuts aren’t available, Typical harvest time is late
nuts from the look for vacuum-packed summer to early autumn;
damaging ones. Without air, nuts can avoid buying nuts in early
effects of light last for up to two years.
and heat. summer.

Buy whole and Roast your own
unprocessed
Avoid buying ready-roasted
These taste the freshest as nuts; instead, roast your
the shell and skin protect the
nut and keep out moisture. own at home (see opposite).

How should I store nuts?

To maintain freshness, keep nuts in an airtight
container in a dark, cool place. Light directly
damages the delicate fat molecules, while heat
and air speed the breakdown reactions. Better still,
store nuts in the freezer in small batches. Nuts
have a low moisture content, so they don’t suffer
the ice-crystal damage that other frozen foods do.

Do Nuts and Seeds Taste Better Cooked?

Do nuts and seeds

TASTE BETTER COOKED?

Bound by oils and with fragile cell walls, nuts and seeds have a pleasant mouthfeel and subtle flavor.

Heating nuts and seeds to above 284ºF (140ºC) packets of oil (called oleosomes) burst open, seeping
triggers the same Maillard flavor reaction (see
pp16–17) that gives other foods an aromatic their contents throughout the nut. A roasted nut
crust and irresistible browned coating with
complex nutty, roasted, and buttery flavors. is softest when warm and the oil most runny,
Nuts can lose moisture during roasting, but
rather than dry out they become creamier. A SOFT NUT so it is best sliced just after cooking.
Inside individual nut cells, microscopic
UNLIKE OTHER NUTS, Add nuts early to stir-fries so that they
ROASTING NUTS AND SEEDS CHESTNUTS ARE HIGH IN brown, but if they reach 356ºF (180ºC), they
MOISTURE AND STARCH, char, a reaction called pyrolysis, and will

SO THEY HAVE A SPONGY tarnish the dish with bitter, acrid flavors.
TEXTURE WHEN

COOKED.

Roasting nuts and seeds is simple, but since they are small, they can reactions be a guide to doneness, and remove them from the heat
quickly burn. Shaking, stirring, and tossing helps to cook them just as they reach a golden brown because they continue to cook
evenly. Let the flavors and aromas released from the Maillard away from heat, known as “carryover cooking.”

IN A FRYING PAN IN THE OVEN IN THE MICROWAVE

The most straightforward way to toast nuts To oven roast, spread lightly oiled nuts and Toasting in a microwave is energy efficient.
and seeds is in a dry or lightly oiled pan. seeds over a baking sheet and cook in a Research also indicates that microwaving
Oil isn’t essential but makes cooking easier preheated oven. Shake and check every is better than roasting for releasing a nut’s
because it helps heat from the pan travel two to three minutes until golden brown. aromas. Spread nuts and seeds on a plate
into the nuts and seeds more evenly. and check and stir at one-minute intervals.
Equipment
Equipment Baking sheet. Equipment
Heavy-based frying pan or skillet. Temperature Microwave-proof plate or dish.
Preheat oven to 355°F (180°C).
Temperature Duration Temperature
Medium-high heat (355°F/180°C). 5–10 minutes. Medium-high power setting.
Pros
Duration Requires less attention than pan-frying or Duration
1–2 minutes. microwave cooking. 3–8 minutes (with checks each minute).
Cons
Pros Uses a lot of energy, unless the oven is on Pros
A speedy method. for another reason; can easily overcook. Fast and effective (and requires minimal
cleanup).
Cons
Needs close attention to ensure Cons
all-over toasting; nuts and seeds can Surface browning is less prominent;
easily overcook. smearing with oil first encourages browning.



HERBS, SPICES,
OILS &FLAVORINGS

In focus 180 // 181 The Science of Herbs, Spices, Oils, and Flavorings

HERBS

Herbs bring a dish to life with their fragrance. We perceive flavor KNOW YOUR HERBS
mostly through smell, which herbs deliver via aromatic essential oils.
Hardy herbs are usually cooked to release
Herbs’ fragrant, flavor-giving chemicals in oil but poorly in water. Cooking with some their flavor, and generally respond better
oil or fat (such as cream) allows herb flavors to to drying (see p182). Tender herbs can
make up just 1 percent of an herb’s weight and infuse a dish far better than without. Herb be used raw for garnishes as well as in
come from tiny oil droplets embedded within flavors are more potent in alcohol than in cooking. Both types benefit from added
their leaves. These essential oils are meant to water. The two main groups oils or fats to bring out their flavor.
repel animals that would eat the plant and are of herbs, hardy and
toxic in large quantities, which is why we use tender, are used in HARDY
herbs in small amounts. Most herbs’ flavor- different ways.
giving compounds dissolve and disperse well
SCIENCE
Rosemary
Fat-soluble Hardy herbs have THE TOUGH LEAVES OF LIFESPAN WHEN Leathery rosemary
Most flavor molecules robust leaves and HARDY HERBS RELEASE FRESH: 3 WEEKS leaves taste unpleasant
BEST USED: FRESH raw, so need to be
in herbs diffuse well tough stalks. FLAVOR MOLECULES cooked with fats to
in oil and fat, which MORE SLOWLY THAN OR DRIED disperse their fragrant
COOKING oils. Strip the leaves and
is why it is easy to TENDER HERBS. chop them before using
infuse oils with COOK HARDY HERBS WITH in baking, or add to the
herb flavors. FATS, AND ADD THEM HARDY pot early when cooking.
EARLY IN COOKING TO HERBS
LIFESPAN WHEN Thyme
ALLOW LEAVES TO SOFTEN Oil glands FRESH: 2 WEEKS Strip the small but
AND RELEASE Herbs have BEST USED: FRESH potent thyme leaves
OILS. glands containing from the tough stalk
oil droplets that OR DRIED before cooking. Or, if
are rich in flavor the sprig is delicate, it
molecules. can be chopped up and
used with the leaves.

LIFESPAN WHEN Sage
FRESH: 2 WEEKS Too strong to eat
BEST USED: FRESH raw, sage leaves make
a delicious garnish
OR DRIED when fried in butter.
Also try cooking
chopped sage with
fatty meats.

Releasing flavor LIFESPAN WHEN Bay
Cutting or crushing FRESH: 2 WEEKS Tough bay leaves
herbs bursts the oil BEST USED: DRIED yield their woody
glands and releases flavor slowly. The fresh
flavor molecules. leaves taste slightly
bitter, so they benefit
from drying. Add dry
leaves to oil at the
start of cooking.

TENDER

LIFESPAN WHEN Mint
FRESH: 2 WEEKS Cutting or crushing
BEST USED: FRESH the leaves releases the
oils for a more potent
flavor. The stalks are
discarded in cooking.

Storing hardy herbs Basil
Wrap hardy herbs in a paper Roll basil like a cigar
towel to absorb excess moisture, and slice it cleanly to
and then keep in an airtight prevent browning.
container in the refrigerator. Unlike other herbs, basil
wilts if chilled, so store
LIFESPAN WHEN it at room temperature.
FRESH: 2 WEEKS
BEST USED: FRESH

SCIENCE COOKING LIFESPAN WHEN Flat-leaf parsley
FRESH: 3 WEEKS This versatile herb is
TENDER HERB LEAVES CHOP TENDER HERBS FOR BEST USED: FRESH excellent used raw as a
AND STALKS DISPERSE A GARNISH JUST BEFORE garnish, but also works
SERVING, OR ADD AT THE well in cooked dishes
FLAVOR MOLECULES END OF COOKING TO KEEP if added toward the
QUICKLY ONCE PICKED end of cooking. Dried
FLAVORS INTACT. parsley lacks flavor;
OR CHOPPED. fresh is best.

Storing tender herbs Tender herbs TENDER Cilantro In Focus: Herbs
Keep tender herbs upright with have delicate HERBS High or prolonged heat
will degrade the flavor
the stems in a small quantity leaves and LIFESPAN WHEN molecules in cilantro,
of water, in the same way you soft stalks. FRESH: 3 WEEKS so add it at the end of
BEST USED: FRESH cooking. Dry or yellow
would keep fresh flowers. leaves have lost their
BUNCH OF HERBS flavor, so discard them.

182 // 183 The Science of Herbs, Spices, Oils, and Flavorings

What’s the best way to

PREPARE FRESH HERBS?

The way in which fresh herbs are handled directly correlates to the intensity and speed of the flavor release.

Herbs’ flavor molecules are found in oil glands onto moisture and oils, and therefore flavor. Delicate

in or on the surface of the leaf (see below). herbs, such as basil and cilantro, have fragile

When damaged, the oil glands erupt, releasing leaves and a milder, more floral scent, and their

the aromatic essential oils, which hold the VARIETY MATTERS flavor evaporates quickly. Many delicate herbs,

herb’s flavor. SOME VARIETIES OF in particular basil and mint, are prone to
There is no “one size fits all” rule when it HERBS ARE LESS PRONE browning because they have high levels of a
TO BROWNING, SUCH AS browning enzyme, polyphenol oxidase (PPO),
comes to preparing herbs, but it is best to which is activated when cells are damaged.
think of them as being “hardy” or “delicate.” NAPOLETANO BASIL.

Hardy herbs, such as rosemary and bay, The table below looks at different ways

generally come from dry climates. to prepare hardy and delicate herbs to help

Their tough leaves are good at holding preserve their flavors.

Oil glands HERB HOW TO PREPARE
in herbs
Delicate · To prevent browning, before
The flavor of delicate These herbs release their cutting you can first steam or
and hardy herbs comes flavor quickly, so avoid blanch herbs for 5–15 seconds
from oils housed in tiny bruising or damaging at 194ºF (90ºC), which destroys
glands on the leaves. them excessively before the browning enzyme. If left on
When damaged, the adding to food, because the heat for too long, however,
glands burst to release they will lose all of their the leaves shrivel.
the herb’s aroma flavor before the rest of
and flavor. the food is cooked. · Dry leaves before chopping,
basil • chives and slice cleanly with a very
Leaf cells cilantro • dill • mint sharp knife to burst the glands
parsley • tarragon with the least collateral
damage.

· Chopped leaves can be doused
in oil to prevent air reaching the
damaged cells, which helps
prevent the browning reaction
(see p166). Plunging chopped
leaves into lemon juice also
reduces the efficiency of the
browning enzyme.

Stomata let air Hardy · For a mild flavor, hardy herbs
pass through Adapted to deal with such as rosemary or thyme can
into the leaf. dry environments, these be added whole to a stew or
more robust herbs release slow-cooking dish, then plucked
their flavor slowly, which out before serving.
gives them greater
versatility in cooking. · For a more intense, quick
bay • oregano release of flavor, finely chop the
rosemary • sage leaves to break more of the oil
thyme glands.

FRESH Two main types of flavor- Underside
BASIL filled oil glands are found of leaf.

on both sides of the leaf.

When Should I Add Herbs During Cooking?

How do I get Use the right amount DRIED ROSEMARY

THE BEST FROM Use around one-third the
DRIED HERBS? volume of a dried herb
as you would fresh.
Apart from bay leaves, herbs’ aromatic substances
readily evaporate when the leaf is dried. Grind before using

When dried, many of herbs’ aromatic molecules Grinding dried herbs in a
escape as as flavor-containing oils evaporate. Also, mortar and pestle before use
each herb has a unique combination of aromatic
substances, which evaporate at different rates, helps release flavorful oils.
so a dried herb can have quite a different taste.
Cook in oil
Hardy herbs from warm climates stand up to
drying better than delicate herbs, as their tough Liberate dried herbs’ fat-
leaves and stems have evolved to lock in moisture friendly flavor molecules
when exposed to the harsh midday sun. Trapped
in the leaf, their flavor molecules are better by cooking them in oil.
retained when dried. The dried herb is then able
to deliver an intense, near complete, flavor profile. Store carefully

Even the herbs most suited to drying suffer from Light and heat degrade flavor.
flavor loss over time. As with fresh herbs, how you Store in an airtight container
treat dried herbs can maximize flavor (see right).
in a cool, dark place.

Make your own

For the most flavorful dried
herbs, dry fresh herbs at
home in the oven.

When should I

ADD HERBS DURING COOKING?

Adding delicate and hardy herbs at the right moment during cooking helps to bring out the most flavor.

As with the preparation of herbs, whether an herb is give time for their flavor molecules to diffuse throughout
delicate or hardy determines how best to cook with it. the food. The flavors of delicate herbs evaporate quickly,

Hardy herbs tend to have powerful “meaty” so they are best added in the last couple of
and hearty flavors, compared to the fruitier, minutes of cooking, or sprinkled on as
more delicate flavor of fresh herbs. The a garnish. If they are added too soon,
resilient structure of their leaves and the nuances of their flavor will be
the potent substances that make destroyed by the heat of the
up their oils mean they are best pan before they get anywhere
added early on in cooking to near the plate.

START OF COOKING END OF COOKING
bay • oregano • rosemary basil • chives • cilantro
sage • thyme dill • mint • parsley
tarragon

184 // 185 The Science of Herbs, Spices, Oils, and Flavorings

Can how I prepare garlic

AFFECT ITS STRENGTH?

Belonging to the same allium family as onions and leeks, garlic contains plenty of pungent sulfur.

As with onions and leeks, flavors are released when garlic

cells are damaged. The plant’s defense mechanisms convert Garlic breath

sulfur-containing proteins into molecules that have a strong When digested, allicin in garlic produces distinctive-smelling
smell and a biting flavor. This fiery garlic-flavored material sulfuric substances that lead to “garlic breath.” It’s hard to mask
is called allicin, which, like capsaicin in chiles (see p190), this smell completely, because the molecules are absorbed into
triggers heat sensors on the tongue. the bloodstream, but there are ways you can reduce its intensity.

Garlic strength What you can do:

The more a garlic clove is damaged or crushed, the more · Some plant-based foods have enzymes that break apart allicin: try
allicin is generated and the more pungent it becomes. combining garlic with mushrooms, parsley, basil, mint, cardamom,
Leaving crushed garlic a minute before using it amplifies spinach, or eggplant.
its flavor as defensive enzymes continue to produce allicin.
At room temperature, the amount of allicin in a damaged · Enzymes in apple and salad greens break down odorous molecules.

· Acid in fruit juice deactivates flavor-generating enzymes.

· Dairy fats in milk trap garlic’s fragrant molecules.

clove peaks at around 60 seconds, then mellows as

allicin and other molecules break down into MINT

more complex flavors. At above 140ºF (60ºC), GARLIC STANDBY
the allicin-generating enzymes are deactivated.

PREPARATION AND PUNGENCY IF KEPT AIRTIGHT, COOL,
A N D D RY, A L L IC IN IN
Different preparations for garlic can have
subtle or significant effects on its pungency DRIED GARLIC POWDER
REMAINS STABLE FOR

MONTHS.

when raw and cooked.

FINELY CHOPPED CRUSHED GROUND PURÉED
Chopped coarsely with a A garlic press produces Mashing in a pestle and Puréeing garlic to
knife, damage is minimal moist, noodle-like shreds, mortar breaks down even a smooth paste maximizes
and little juice is produced. damaging many cells. more cells than pressing.
cell damage.
· Raw: With a mellow flavor, this · Raw: Flavor is strong but sweet. · Raw: Flavor intensity is slightly
works well in dressings, provided When pressed to this consistency, stronger than crushed garlic. · Raw: Cell damage is extensive,
there are no large pieces. it disperses easily in dishes. It disperses well in dishes. increasing allicin production to
create intense flavor and heat.
· Cooked: When heated, it remains · Cooked: Moderate pungency. The · Cooked: When heated, this has
mild and sweetens as starches damp slivers can scorch, so cook mild heat and sweetness, and · Cooked: Heating mellows the
break down sugars. lightly in oil before adding liquids. offers strong, complex aromas. intensity dramatically, and
sweetness is spread through food.

“The ancient tradition of “curing”
garlic by hanging up chains of intact
bulbs for two weeks allows sugars
and flavor-containing compounds
”to pass from the stems into the
cloves, and garlic to develop
a more intense
flavor.

186 // 187 The Science of Herbs, Spices, Oils, and Flavorings

How can I get the most

FLAVOR FROM SPICES?

Most spices are hardy ingredients that are laden with aromatic flavor-carrying substances.

Spices come from any part of the plant apart from whole spices releases defensive enzymes to trigger a

the leaf, such as the root, bark, or seeds, and can chain reaction of flavors, just as it does with garlic.

be used either whole or ground. Most whole Cooking whole spices for a long time also

spices come predried, which is sometimes A GOOD SOAK breaks apart the cells, and high heat triggers

done at a very high temperature. However, DRIED MUSTARD SEEDS Maillard browning (see p16), creating exciting
unlike herbs, spices benefit from drying, GIVE A STRONG SCENT ONLY deep, nutty aromas.
developing a more intense flavor. ONCE HYDRATED, SO THEY
BENEFIT FROM PRESOAKING In ground spices, the crushed cells have
Being from a part of the plant that has already started their flavor chain reactions,
FOR 3–4 HOURS.
deliberately tough defenses from the so these need to be treated with greater care.

elements, spices are inherently tough, so their Follow the tips below to get the most out of

full flavor often needs to be coaxed out. Damaging both whole and ground spices.

WHOLE SPICES GROUND SPICES
Encased in fibrous plant tissue,
flavor needs to be drawn out. Flavor escapes more quickly from
precrushed spices.
CRACKING,
CRUSHING, STORE GROUND
OR GRINDING SPICES IN AN
WHOLE SPICES
KICK-STARTS AIRTIGHT
THE FLAVOR- CONTAINER.

MAKING KEEP IN A COOL,
PROCESS. DARK PLACE TO
PRESERVE FLAVOR
WHOLE SPICES
BENEFIT FROM LONG MOLECULES.
COOKING TIMES, SO
FLAVOR REACTIONS FROM
THEY ARE BEST THE PRECRUSHED CELLS
ADDED EARLY IN HAVE ALREADY STARTED,
SO ADD LATER IN COOKING
COOKING.
TO REDUCE THEIR
HIGH HEATS COOKING TIME.
DEVELOP AND
RELEASE FLAVOR. GROUND SPICES
BURN EASILY,
CARDAMOM SEEDS
SO AVOID VERY
HIGH HEATS.

GROUND CARDAMOM

Why Is Saffron So Expensive?

Aromatic vapors rise Why do recipes often say to add
from the oil and spice.
SPICES TO OIL AT
THE START?

Cooking in oil helps to carry flavor through the dish.

Cooking whole or just-crushed spices in oil before other
ingredients helps heat to pass into the spice evenly and
avoids scorching. Most importantly, spices “bloom” in oil:
flavor molecules are created in the heat and dissolve in
the oil, enhancing the flavor of both oil and spice (see left).

A flavor carrier

As with herbs, for most spices, the majority of their

Oil Flavor molecules Base of pan characteristic flavor-carrying substances dissolve in oil
spread into the oil. Heat damages spice cells, better than water and the flavor molecules permeate out
triggering flavor reactions. into the oil. For example, dried chili flakes, cooked in oil
for 20 minutes at 200ºF (93ºC), release twice the amount

WHEN A SPICE “BLOOMS” of fiery-hot capsaicin as when cooked in water.

Why is saffron

SO EXPENSIVE?

Much imitated, authentic saffron has a lingering, penetrating hay-like aroma with notes of cinnamon and jasmine.

The thin, dark red saffron threads are the tiny “stigmas” 21/2 ACRES 1.7OZ
that grow out of the Crocus sativus flower. Harvested 1 HECTARE 48 GRAMS
individually by hand, each bloom makes only three stigmas:
it takes an astonishing 100,000 to 250,000 plants and over Using the thread- SAFFRON CROCUS DRIED
200 hours of labor to yield 1 pound (0.45kg) of spice. like stigmas to make SAFFRON
the spice, 21/2 acres
This precious commodity has over 150 flavor-carrying of plants produce a 2–3 TONS
substances. For everyday cooking, turmeric makes a good tiny yield of saffron.
yellow-colored substitute but has a harsher flavor, so it DRIED
can’t be swapped for saffron in sweet dishes. Unusually 21/2 ACRES TURMERIC
for spices, saffron’s flavor molecules dissolve better 1 HECTARE
in water than oil. Steeping saffron for 20 minutes helps
rehydrate the threads and improves flavor. Soaking isn’t The rhizomes that
essential, but can help you get all of saffron’s flavor. are dried and ground
to make turmeric
“Saffron has over 150 different produce quite a
flavor-carr ying substances that sizable yield. TURMERIC RHIZOME
give the spice its uniqueness.”

In focus 188 // 189 The Science of Herbs, Spices, Oils, and Flavorings

CHILES

Chile peppers’ active ingredient, capsaicin, is a toxic irritant that produces a KNOW YOUR CHILES
burning sensation when we come into contact with it. However, in moderation,
capsaicin creates an enjoyable spiciness. The most well-known rating of a chile
pepper’s “hotness” is the Scoville scale,
Capsaicin evolved to protect peppers from Contrary to popular belief, the seeds of a chile which is measured in units of SHU. The
being eaten, and does repulse nearly every pepper are not the hottest part, and, in fact, strength of a species of chile can vary greatly.
mammal. We humans, however, have put have little, if any, heat whatsoever. The flesh Below is a selection of chiles from around
chiles into our food for at least 6,000 years. of the pepper isn’t particularly hot either; most the world that are popular in cooking.
Capsaicin doesn’t actually have a flavor or of the capsaicin is produced in tiny droplets
smell—when it enters the mouth it simply on the soft, cream-colored placenta in the SCOVILLE SCALE
causes pain by directly binding onto the center of the fruit (see below). While most
nerves in the mouth and tongue that detect cooks believe that removing the seeds will Scotch bonnet
pain from heat sources. This tricks our brain reduce the heat of a chile pepper, it is really These very hot
into sensing burning heat (see p190). Despite the action of scraping away the white placenta peppers are sweet
this, chili heat is a popular flavoring. that creates this effect. in flavor. Add them
whole to stews and
100,000–350,000 SHU curries, but take care
3/4–11/4IN (2–3CM) not to burst them and
IN DIAMETER add too much heat.

SCIENCE COOKING BITTER TASTES 100,000–350,000 SHU Thai chiles
1 1/2 – 3 I N Often called “bird’s
CAPSAICIN, THE HEAT- COOK CHILES IN OIL REMOVING SEEDS FROM A eye chiles,” these
CONTAINING ELEMENT OR FAT-CONTAINING CHILE DOESN’T ACTUALLY (4–8CM) LONG tiny peppers are very
OF CHILES, DISSOLVES SAUCES SO THAT HEAT hot. Their flavor
AND FLAVOR SUFFUSE REDUCE HEAT, BUT THE complements citrus
WELL IN OIL, BUT SEEDS DO CONTAIN and coconut, and they
VERY BADLY IN THROUGH THE BITTER-TASTING are often used in Thai
WATER. DISH. SUBSTANCES. curries.

Chili and onion FRESH Stem Piri piri
flavoring Although most piri
Skin piri plants are now
Mostly flavorless, the 50,000–100,000 SHU found across Africa,
skin will brown and 3–4IN the species is originally
char when roasted. from South America.
(8–10CM) LONG Piri piri sauce is
originally from Portugal.

Flesh 30,000–50,000 SHU Aji limon
This slightly watery 2–3IN Sometimes referred
part of the chile adds to as the “lemon
crunch and texture (5–8CM) LONG drop” pepper, these
Seeds Peruvian chiles have
White and flavorless, 10,000–25,000 SHU a citrus-like taste—
the seeds carry almost 11/4 – 2IN hence their name. Use
no capsaicin. them to add spice to
Placenta (3–5CM) LONG meat dishes and stews.
The fiery hot capsaicin is
produced and stored as 3,500–10,000 SHU Serrano
minute droplets in the 2–3IN (5–8CM) LONG Serrano peppers have
white placenta. a brighter, fresher
1,500–2,500 SHU flavor than many other
Chipotles are 3/4 –11/4IN ( 2– 3CM) varieties, so are often
smoke-dried eaten raw or in cold
jalapeño chiles IN DIAMETER dishes. Smoking or
roasting will enhance
THAI CHILE SCIENCE COOKING 100–500 SHU their flavor. They are In Focus: Chiles
3–4IN a key ingredient in
DRYING CHILES REMOVE STEMS AND SEEDS Mexican cuisine.
INTENSIFIES FLAVORS, AND TOAST DRIED CHILES (8–10CM) LONG
PRODUCING COMPLEX UNTIL THEY BLISTER. THEN Jalapeño
SOAK THEM, BLEND, AND Jalapeño peppers can
EARTHY AND NUTTY be quite variable in
FLAVORS. ADD TO A SAUCE. heat level. In Mexican
cuisine, when they are
smoke-dried, they
are referred to as
“chipotle” peppers.

Cascabel
This round chile has
a nutty, sweet flavor
and is small in size. It
pairs well with meat,
chicken, and fish, and is
often toasted and used
in sauces and stews.

Pimiento
Milder than most
chiles, pimiento
peppers originate
from Spain. They are
sweet, succulent, and
aromatic, and are often
used to stuff olives.

DRIED

190 // 191 The Science of Herbs, Spices, Oils, and Flavorings

How can I tame food that’s What’s the best way to

TOO HOT? TAKE AWAY
CHILE HEAT?
As with oversalting, it can be hard to counteract chile
heat while cooking, but there are a few tricks you can use. Learn science-based strategies for reducing chile burn.

Unfortunately, it is hard to eliminate the effect of The “heat” we feel from chiles is due to a substance
the burning capsaicin molecules in chiles (see right). called capsaicin, which has the devious capability to attach
to heat-sensing receptors on pain nerves (see below). To
Prevention is the best cure—when cooking with fresh your brain, physical burning and chile “heat” are identical
or dried, whole or flaked chiles, try to add only a small sensations. Most of the accepted antidotes for chile burn—
quantity at a time, and then taste the dish and add a including alcohol and fizzy drinks—make it worse, but if
little more if necessary (spiciness will lessen as the you’re in agony, there are a few quick fixes to lessen the
dish cools). If you have already added too much chile pain (see right). Time is the best healer: the burning sensation
while cooking, there are a number of different created by most chiles will dull after three minutes, and
ingredients you can add to tone down, or distract from, after 15 minutes it should completely disappear.
the heat (see below). When seasoning spicy dishes, also
bear in mind that chile heat takes longer to kick in than WAYS TO EASE CHILE BURN
other tastes—there is a short delay before the capasicin
triggers the heat receptors on the tongue (see right).

Water or vegetables Ice
Placing an ice cube or two in your mouth
Adding water or more vegetables to the can negate the burning sensation after
sauce will dilute capsaicin molecules you’ve eaten too much chile. The ice cubes’
over a wider area, dispersing their heat. freezing temperature confuses your brain
into ignoring some of the chile heat.
Cream or yogurt Milk and yogurt
Fats and casein proteins in milk and yogurt
Dairy fat globules, surrounded by absorb capsaicin, preventing more of its
emulsifying casein proteins, soak fiery molecules from bonding with pain
up some of the capsaicin molecules. receptors. Their fridge-cold temperature
also has a soothing effect on your tongue.
Limit salt

Salt increases the sensitivity of heat
receptors on the tongue to capsaicin,
increasing chile’s fiery power.

Honey or sugar Mint
Just as capsaicin affects the
Intensely sweet ingredients, such as heat-sensitive nerves in your mouth,
honey or sugar, reduce the sensitivity of heat so the menthol in mint stimulates your
receptors on the tongue, balancing chile heat. cold-perceiving nerves. Chew on a few
fresh mint leaves, or add mint to a cooling
Avoid acid yogurt sauce, to help counteract fiery
chile sensations.
Acidic foods, such as vinegar and citrus juice,
trigger heat-sensitive nerves on the tongue.
Add alkaline baking soda to reduce heat.

NO RELIEF 108°F What’s the best way to take away chile heat?

CARBONATED DRINKS AND (42°C) is the temperature THALAMUS
FIZZY BEERS SENSITIZE at which heat-pain SIGNALS THE BRAIN
THE TONGUE EVEN MORE, receptors are usually The thalamus relays
SO OFFER LITTLE RELIEF activated. pain signals to other
FROM THE HEAT. parts of your brain.

“To your brain, physical #3
burning and chile heat are
Pieces of chile
identical sensations.”

Food particles
travel to taste buds.
Capsaicin molecules stimulate
pain receptors not taste buds.
Pain receptors
are on nerve cells.

#2

Tongue
papilla

Taste buds

#1 The effect of NERVES
capsaicin on the tongue TRANSMIT PAIN
Long pain nerves
The chemical that gives chiles their heat, capsaicin, fire signals into the
works by bonding with heat-perceiving receptors on
pain nerves in the tongue. These sensors normally only spinal cord.
activate at temperatures above 108°F (42°C), so your
nerves and brain perceive capsaicin as burning heat. The spinal cord contains nerves that
relay information to your brain.

In focus 192 // 193 The Science of Herbs, Spices, Oils, and Flavorings

OIL AND FAT

As well as suffusing flavor molecules from other foods, oils and fats carry KNOW YOUR OIL AND FAT
their own flavors, too, making them an ingredient in their own right.
Unrefined oils contain minerals, enzymes,
Oils are fats that are liquid at room such as chili, lemon, rosemary, and basil. and flavor-carrying impurities, which have
temperature and are typically plant-based. But more than this, oils and fats can cook a tendency to burn. All oils and fats burn
Other cooking fats are usually solid and food at very high temperatures, but they at a different temperature, known as the
animal-based. Oils are generally rich in must be treated with care. When they are “smoke point.” These smoke points are
unsaturated fats, while animal fats are high heated to their limit (see “smoking point,” listed below to help you choose the right
in saturated fats, which can raise cholesterol. right), molecules are ripped apart and the oil or fat for your particular cooking method.
Both enhance the taste and mouthfeel of oil or fat disintegrates and darkens, giving
food. Flavor molecules from herbs and spices off acrid vapors and tasting foul. Faint OILS
dissolve easily in oil, so flavors suffuse a dish blue smoke signals that a pan should
fully. Oil is easy to infuse with ingredients be taken off the heat. Extra virgin

SCIENCE COOKING SMOKE POINT: olive oil
320ºF (160ºC) This thick, highly
OIL CARRIES FLAVOR OIL FORMS A LUBRICATING FAT: 91.5G PER 100G flavorful oil has a low
MOLECULES AND FILM BETWEEN FOOD AND smoke point, making it
CONDUCTS HEAT unsuitable for frying. It
METAL TO STOP FOOD is best used for drizzling
EFFICIENTLY TO THE FROM STICKING AND and as a base for dressings.
SURFACE OF FOOD.
FALLING APART. Olive oil
More versatile than
OIL SMOKE POINT: virgin olive oils, cooking
390ºF (200ºC) olive oil (a mix of
FAT: 91.5G PER 100G unrefined and refined
oils) has a higher smoke
point, so it can be used
to impart a mild olive
flavor to fried foods.

SMOKE POINT: Canola/rapeseed oil
400ºF (205ºC) This general-purpose oil
FAT: 91.7G PER 100G has earthy, nutty flavors,
but lacks taste when
overrefined. It has a
fairly high smoke point
and can be used for
frying and roasting.

Flavor enhancer SMOKE POINT: Peanut oil
Good-quality olive oils offer 450ºF (230ºC) A high smoke point
complex fruity, peppery, green, FAT: 91.4G PER 100G makes this ideal for
and floral flavor sensations. stir-frying food at a high
Best storage temperature. Unusual
Olive oils are best kept in bottles for nut oils, its mild,
with green or dark glass to prevent nutty flavor is retained
UV light from reaching the oil and even after cooking.
accelerating the breakdown of
flavor molecules. Coconut oil
Increasingly popular,
SMOKE POINT: this heavy oil melts
350ºF (175ºC) from solid to liquid at just
FAT: 97.3G PER 100G above room temperature.
If unrefined, coconut oil
can smoke excessively
during frying.

SCIENCE SATURATED FATS

PROTEIN TRACES AND SMOKE POINT: Butter
OTHER SOLIDS IN FATS 350ºF (175ºC) This has an unparalleled
REACT WITH HEAT TO FAT: 82.9G PER 100G flavor in sauces, baked
goods, and pastries.
SPEED BROWNING Up to 16 percent water,
AND FORM NEW butter has a low smoke
AROMAS. point that is unsuitable
for frying at a high heat.
Adding butter
Butter enhances Ghee (clarified butter)
Nutty-flavored ghee is
flavor and texture, widely used in Indian
giving pastry cooking. Water is removed
to create this “clarifed”
added flakiness. butter, leaving only fat.
It has a high smoke point
COOKING SMOKE POINT: useful for frying.
445ºF (230ºC)
SATURATED FATS ARE FAT: 100G PER 100G
BEST USED TO ENRICH
AND ADD TEXTURE TO BUTTER Lard and tallow
Rendered from pork fat
SAUCES, PASTRIES, SMOKE POINT: (lard) or beef fat (tallow), In Focus: Oil and Fat
AND BAKES. 365ºF (185ºC) LARD these fats are solid at
400ºF (205ºC) TALLOW room temperature.
FAT: 98.8G PER 100G Highly stable, they can
withstand repeated use
in deep-fat frying.

EXTRA VIRGIN
OLIVE OIL

194 // 195 The Science of Herbs, Spices, Oils, and Flavorings

Why are some

OLIVE OILS BETTER QUALITY
THAN OTHERS?

“Extra virgin” denotes quality, but we are often confused by terms such as “cold pressed” and “first pressed.”

When olives are harvested for oil making, they are ground speeds the rate at which oil turns rancid. “Cold pressed” or
into a yellowish-brown sludge called a paste. Traditionally, “cold extracted,” a label that attracts a high markup, means
hemp mats were soaked in this paste and squeezed with a an oil has not been warmed above 81ºF (27ºC). For quality
press to force out the oil. Today, most olive oil is extracted guarantee, choose oils labeled “virgin”: olives are fresh
by spinning the paste in a centrifuge. This faster method with pressed or spun only once to extract the best-quality oil.
less air exposure yields better quality. Warming the paste Acid levels indicate that fat molecules have broken
makes it easier to draw oil out, but this can be at the expense into fatty acids due to damage or poor processing.
of flavor because heat causes fragrances to evaporate and The top virgin oil grades are low acidity (see below).

EXTRA VIRGIN “Virgin olive oils are
OLIVE OIL pressed or spun only
Reserved for oil rated as once to extract the best-
having excellent flavor. quality oil. No virgin oil
To be awarded “extra,” can be pressed more
it needs an acidity of than once—the words
less than 0.8 percent.
‘first pressed’ are
VIRGIN OLIVE OIL marketing spin.”
This must meet
international taste How do I pick the most
standards, and it has flavorful virgin oils?
acidity levels below
1.5 percent to indicate Picking the best, most flavorful, fresh, and
overall quality. fruity oil is not straightforward. A dark green
color does not mean it is good—some of the
OLIVE OIL finest oils are light colored. Look for a harvest
Below“virgin” standards, date within the past 12 months for the
these are often refined freshest oil or, failing that, a best-before date
to remove impurities. two years in the future. Unfiltered olive oil
Lacking flavor, refined may have sediment in the bottle, but this
oils withstand high doesn’t mean it has a better flavor and it
cooking heats. may turn rancid faster. Taste first to judge
the quality.

What’s the Best Way to Store Olive Oil?

What’s the best way to

STORE OLIVE OIL?

Like wine, delicately flavored unrefined oils will turn rancid and musty tasting if carelessly stored.

Heat, light, and air all destroy flavors in oils. reactions, and light wreaks havoc on the fragile
Although few in overall number, oil aroma
molecules havea strong effect on the nose, N molecules in unrefined oils. Attractive-
and come from the squeezed fruit, seed, looking green olive oils contain plenty
or nut. The flavors in oil are best when
fresh and do not evolve or improve with A LITTLE HELP of the leafy green plant pigment
age, so storing oils is about preserving the
aromas for as long as possible. BOTTLES SEALED WITH A chlorophyll, which absorbs even more
BUBBLE OF INERT GAS, of the sun’s energy, making green oils
Oxygen is disastrous for oil flavors, SUCH AS NITROGEN OR prone to turning rancid more quickly.
so always keep oils stored in an airtight ARGON, AT THE TOP HAVE Even when the bottle is cool and
container. Heat speeds up the flavor-tainting
A LONGER SHELF completely airtight, the energy from the

LIFE. sun’s rays, especially the most powerful UV

rays, is enough to trigger oxidation (see below).

OLIVE OIL IN A Triple-limbed The molecular
DARK BOTTLE fat molecules structure of oils

Bottle type DID YOU KNOW? At a molecular level, oils are mostly
made of a triple-limbed fat molecule,
The darker the bottle the better.
Dark brown blocks out more light triacylglycerol. Oxygen, light, and
than green. Plastic slowly leaches heat can break off limbs, and each
air, so glass is best.
limb turns into a highly reactive
Temperature fatty acid that sets off a chain

Heat hastens flavor-tainting reaction, creating rancid off-flavors,
reactions, so keep oils away a process known as oxidation.
from heat sources and sunlight.
When oxidized, the three
Exposure to air limbs break down to
produce rancid flavors.
Oxygen destroys oils’ flavors.
Always store oil in an airtight Some oils keep better if chilled
container.
High heats are always detrimental to oil quality, but
depending on the type of oil, colder is not always better.
· The best storage temperature for unrefined (virgin and extra virgin)

olive oil is 57–59ºF (14–15ºC)—cooler than room temperature but
warmer than a refrigerator. Olive oils do not benefit from being chilled
because when the temperature drops, the most stable and light-
resistant fats in olive oil turn solid first, leaving the more delicate
and vulnerable triacylglycerol molecules behind as a liquid.
· Refined cooking oils have had most of their flavors removed along
with any impurities when they were filtered or cleaned, giving them
a longer shelf life. Unlike other oils, nut and seed oils tend to last
longer in a refrigerator, although they may turn cloudy or solidify.

196 // 197 The Science of Herbs, Spices, Oils, and Flavorings

Why does food cook

FASTER WHEN IT’S FRIED?

Frying is the favored technique of time-pressed cooks—the chemistry of oils explains
the speedy nature of cooking in a frying pan or deep-fat fryer.

Frying is one of the fastest ways to complexity of flavorto the food. Butter is “DOUBLE” COOKED
cook food. It’s quicker than water-based one of the most flavorful fats, but it’s best
techniques because oil reaches to choose a high-smoke-point oil FRENCH FRIES ARE OFTEN
temperatures far greater than water: for frying (see pp192–193), because COOKED FIRST AT 325ºF
frying typically operates around 348– this will allow the oil to heat to the high (160ºC), THEN BRIEFLY AT
445°F (175–230°C), compared to a temperatures necessary for browning 375ºF (190ºC) TO COOK THE
maximum of 212°F (100°C) for boiling and caramelization without the butterfat
in water. Oil also heats up faster than burning. Oils can be reused several times INSIDE WITHOUT THE
water and transfers its heat into food and get better with use. As some fat SURFACE BURNING.
far more effectively than even the molecules react in heat, they develop
hottest oven. pleasant flavors and penetrate further
into food, giving a denser crust.
Frying for flavor
Comparing cooking rates COOKING TIME FOR WHOLE CHICKEN:
Cooking in oil is not just about speed
and heat, however. When the surface The table compares the rate at 25 40 90 90–120
of a frying piece of food—bare or which different cooking mins mins mins mins
battered—hits 284°F (140°C), Maillard
browning begins (see pp16–17) and the methods will cook a whole DEEP- PRESSURE BOILING OVEN
food starts to form a flavorful, crunchy chicken. Moisture must steam FRYING COOKING
surface. At 329°F (165°C), sugars in the
food caramelize, adding extra away from the surface of the
food before it can exceed

212ºF (100ºC), when it will
start browning.

Why is fried food

BAD FOR YOUR HEALTH?

Frying is a notoriously unhealthy cooking method—but there are ways to reduce the health risks.

Without a doubt, fried food contains more energy after it is taken out of the frying pan or deep-fat fryer.

(calories) than food cooked by any other means. This means that promptly blotting away excess

This is because oil is absorbed into the food oil (using paper towels) is a good way to

during cooking. Fat isn’t evil, but too much COUNTING CALORIES reduce the fat content of fried food.
of it certainly isn’t good for the waistline— Calories aside, frying can also be bad for

gram for gram, fat contains more than twice JUST ONE TABLESPOON OF your health if the oil gets too hot. If hot
as many calories as protein or carbohydrates. FAT CONTAINS 120KCAL oil is giving off a blue haze or smoke, it is
Super-heated steam bursts out of frying food reaching its smoke point (see pp192–193)
as it cooks in the hot oil (see pp76–77), (500KJ), SO USE AS LITTLE and harmful, acrid-tasting chemicals are
OIL AS POSSIBLE AND FRY
limiting how much oil penetrates into the starting to form. When frying, choose oil
IN MODERATION.

food during cooking—around 80 percent of the with a high smoke point (see pp192–93), opt

oil that soaks into food does so in the first few seconds for healthier fats, and heat oil carefully.

“ Reusing oil gives fried food
an even better taste because
partly oxidized oils add extra
flavor. When too many fats have
oxidized, the oil becomes rancid
”and should be discarded.

198 // 199 The Science of Herbs, Spices, Oils, and Flavorings

How does

ALCOHOL ENHANCE FOOD?

Its inebriating effects aside, alcohol has an important place in the kitchen thanks to the flavors it gives to food.

Wines, beers, and ciders enhance stews, sauces, CURED
and desserts not only from the actual alcohol MEAT/
they contain, but by imparting sweetness from HAM
a drink’s sugars, sharpness from its acids, and RED MEAT
savory notes from its amino acids, which develop POULTRY
as they interact with the food. FISH
SHELLFISH
Careful cooking CHEESE
SAUCES
Alcoholic drinks need gentle simmering because TOMATO-
many subtle aromatic flavor molecules evaporate BASED
quickly, potentially concentrating less-pleasant SAUCES
tastes, and turning the remaining liquid DESSERTS
excessively acidic. Wine that is reduced for too
long can develop an astringency from tannins, CIDER
the substances fruit produce to deter parasites, BEER / ALE
so avoid cooking with vintage wine because LAGER
its nuanced flavors will vaporize in the other WHITE WINE
ingredients. Use the chart, right, as a guide RED WINE
to flavor pairings between alcohol and food. WHISKY

Cooking with alcohol

The chart, above, shows how drinks pair with different foods
during cooking. The bigger the circle, the better the pairing.

30% What happens

is the minimum alcohol WHEN I FLAMBÉ FOOD?
strength needed to
flambé food. Flambéing is a showy way to liven up a dish.

NO FLAME While flambéing is an impressive spectacle, to light. Alcohol fumes rise quickly, so keep
the technique is straightforward. High-strength hair and sleeves out of the way and keep a
WINE AND BEER WON’T warm or room-temperature liquor is poured large metal lid on hand in case of flare-ups.
FLAMBÉ BECAUSE THEY into a nonsimmering pan and ignited by
GIVE OFF INSUFFICIENT tilting the pan into a flame or by igniting A better taste?
FLAMMABLE VAPORS TO with a long-handled lighter. It is not the liquid
that burns, however, but the alcohol vapors Flavor-wise, flambéing does little. The
CATCH FIRE. as they evaporate: bluish tongues of fire hover flames can reach 500ºF (260ºC), which is
slightly above the dish, consuming the fumes. more than enough to char the surface of
the food and give a scorched taste, but in
It is best to pour off most of any existing practice most of the heat hovers above
sauce that is in the pan before adding the the food. “Blind” taste tests show that
alcohol because the concentration of alcohol flames don’t improve taste in any way,
in the sauce needs to be sufficiently high for and many chefs consider flambéing more
the dish to ignite—if there is less than 30 showmanship than cooking, done purely to
percent alcohol in the sauce, it will be hard build anticipation and impress the diners.