Cooked: A Natural History of Transformation (24 page)

In the story of a stew, the pot is the stage
and water the hero (or the nonhuman hero, anyway), the elemental actor that supplies
unity of character and makes things happen. True, there are a few braises that call for
no added liquid, but, as long as they cook slowly in a
covered pot,
liquid will soon appear anyway, in the form of juices seeping from the meat or the
vegetables, and these liquids will perform ably in the role of water.

Which in cooking is protean: creative and
destructive and ultimately transformative. Water that has been domesticated by being
confined to a pot might not seem as potent as the wild water that carves canyons and
coastlines, but its powers are impressive even so. Consider some of the things water can
do once it has been captured in a cook pot and that pot has been put on a fire:

First, the water will conduct the
fire’s heat, evenly and efficiently, conveying it from the walls of the pot into
every cranny of whatever’s being cooked in it. If that happens to include dried
seeds, water will bring them back to life—sometimes literally, by inspiring them to
germinate, or figuratively, by making them soft and plump enough to eat. But water,
sufficiently heated, can kill, too, dispatching dangerous bacteria in our food. It will
sterilize meat and detoxify plants and fungi. It will leach out salt and bitterness.
Water in a pot can bring together far-flung taxonomic kingdoms, marrying plants and
animals and fungi, so that they might act on one another—swap flavors, alter textures.
Given enough time and the proper amount of heat, water will break down the toughest
fibers in both plants and animals, transforming them into food. Given still more time,
it will break these foodstuffs down into a rich paste and, eventually, into a tasty,
nutritious liquid: a dispersed phase of its continuous self. But what water breaks down
it also reassembles along new lines.

Water will extract molecules from one
ingredient and diffuse them so that they might encounter and act on the molecules in
another ingredient, breaking some chemical bonds and forging new ones, which might be
aromas, flavors, or nutrients. In a pot, water is the medium of flavor as well as heat,
allowing spices and other seasonings to get around and make their presence felt. It also
dilutes the
effect of the most pungent spices, like peppers, making
them more amenable. Given heat and time, water softens, blends, balances, harmonizes,
and marries.

With so much going for it, you would think
water alone would be more than adequate as a braising liquid. And it is, sometimes. In
fact, Samin was of the opinion that tap water was underrated as a braising liquid, while
chicken stock, the default in most kitchens, was used way too much.
^*

“I don’t understand why you
would want everything you braise to taste like chicken, unless you’re braising
chicken,” Samin mentioned one afternoon, when we were getting ready to put a
Moroccan lamb stew into the oven. The dish already promised plenty of flavor. To its
base of mirepoix and garlic, we had added a bunch of toasted Moroccan spices, and then
laid out some orange peels, dried apricots, cilantro stems, and, on top of that fragrant
bed, the well-browned cuts of lamb. So we dispensed with stock and used some water, and
a splash of white wine, instead. “Eventually that liquid is going to turn into
something rich and delicious—it doesn’t need to taste like chicken!”

As the continuous phase in our lamb stew,
water’s role is to blend and balance some pretty wild flavors, forging them into a
familiar sense experience: the flavor of Moroccan food. Most of us instantly recognize
such basic flavor profiles, and indeed depend on them to figure out what we’re
eating and to feel comfortable doing so. If the omnivore’s dilemma is to determine
what is good and safe to eat amid the myriad and occasionally risky choices nature puts
before us, then familiar flavor profiles can serve as a useful guide, a sensory
signal of the tried and true. To an extent, these familiar blends of
flavor take the place of the hardwired taste preferences that guide most other species
in their food choices. They have instincts to steer them; we have cuisines.

This at least is the theory of culinary
flavor advanced by Elisabeth Rozin, the cookbook writer, and her former husband, Paul
Rozin, the social psychologist. “Flavoring a dish with soy sauce, for example,
almost automatically identifies it as Oriental,” she points out in her book
Ethnic Cuisine: The Flavor-Principle Cookbook
. But the sprawling Eastern
empire of soy has many nations within it: “If you add garlic, molasses, ground
peanuts and chilies to the basic soy sauce, you will create a taste characteristically
Indonesian,” she points out. And if fish sauce and coconut milk are added instead,
the dish becomes Laotian, and so forth. Every cuisine has its characteristic
“flavor principle,” Rozin contends, whether it is tomato-lemon-oregano in
Greece; lime-chili in Mexico; onion-lard-paprika in Hungary, or, in Samin’s
Moroccan dish, cumin-coriander-cinnamon-ginger-onion-fruit. (And in America? Well, we do
have Heinz ketchup, a flavor principle in a bottle that kids, or their parents, use to
domesticate every imaginable kind of food. We also now have the familiar salty-umami
taste of fast food, which I would guess is based on salt, soy oil, and MSG.) But as soon
as we encounter a familiar flavor principle, we know what we’re eating and can
relax in the knowledge that our dinner has been prepared according to a set of
time-tested rules, and so probably won’t kill us or make us sick.

These flavor principles always involve the
marriage of at least two aromatic plants and often many more. That may be because no
single seasoning can ever mark a food as having completed the necessary journey from the
risky realm of raw nature to the safety of cooked culture. What we seem drawn to is the
combination of flavors that only
Homo sapiens,
experimenting over time, could
concoct from whatever nature has to offer locally. And much like any other artifact of
culture—a vase, a melody—these combinations most appeal to us when
they exhibit a kind of balance or symmetry—in this case, between sweet and sour, say, or
bitter and salty.

Particularly in the case of the more
elaborate combinations of flavor, such as in our Moroccan stew, the greatest conductor
of flavor principles is the element of water: it is what weaves together the differently
colored threads of taste into a familiar pattern, gives them their unity. A cooking oil
can achieve somewhat similar results (and is often itself an important element in a
flavor principle), but water is the principle medium of taste; indeed, for the tongue to
taste any molecule, it must be soluble in water. (Strictly speaking, “taste”
is limited to one or more of the five senses perceptible to the tongue: sweet, salt,
sour, bitter, and umami. Flavor is a broader category, encompassing smells as well as
taste, with the result that our response to it depends less on our genes than on our
experience.)

But if plain old water can do all this for
the flavor of a stew or soup or sauce, then why do so many cuisines resort so often to
animal-enhanced waters, in the form of a stock or broth? Cooks will tell you that stocks
add a quality of richness or intensity or “depth” to a braise or stew or
sauce, making a savory dish that much more savory. It also adds “body,” or
substance. “Stock is everything in cooking,” the great French chef Auguste
Escoffier famously declared, “Without it, nothing can be done.” This is why
many great restaurants employ a “saucier,” a cook whose entire job consists
of making stocks. To buy such a foundational ingredient would be out of the
question.

It’s curious that this one ingredient
of a dish consists, in effect, of a whole
other
dish—one with its own recipe,
its own cook pot, its own liquid, and its own foundation of aromatic vegetables, notably
including our old friends onion, carrot, and celery. To make a stock to add to a braise
or a sauce, which Samin and I did on several occasions, feels like embarking on an
infinite culinary regression, taking
us all the way back, again, to
the chopping of onions, browning of meat, and adding of liquid. But this process of
repeating reductions—cooking things down in water, extracting their essences, and then
reducing them yet again—seems to be how the deepest, purest layers of flavor are
formed.

So what exactly is it about stock that makes
it so indispensable? What does it really mean to say it gives “body” or
“depth” to a pot dish or sauce, or makes something taste more
“savory,” as stocks undeniably do? What, in other words, is so special about
this particular liquid we call stock?

I suspect it’s something more than the
flavor of the animal (or vegetables) on which the stock is based. As Samin’s
feelings about chicken stock suggest, the flavor of chicken is not necessarily a plus,
and often goes unnoticed in the finished dish anyway. Indeed, one of the reasons that
chicken or veal is usually the default stock owes to their relative
lack
of
flavor, at least when compared with beef or pork, as well as to the fact that their
young bones contribute comparatively more gelatin to a dish or sauce, thereby adding to
their body. But there had to be something more to it than that, and after I spent some
time researching the chemistry of meat stocks and the physiology of our sense of taste,
it became (you’ll forgive me) clear as consommé: The most important quality that a
long-simmered stock contributes to any dish to which it has been added is the seductive
and still somewhat mysterious fifth taste called umami.

Umami has been recognized as a full-fledged
taste in Japan since 1908. That was the year that a chemist named Kikunae Ikeda
discovered that the white crystals that form on dried kombu, a kind of seaweed that has
been used as a base for soups and stocks in Japan for
more than a
thousand years, contained large amounts of glutamate, and that the savory taste of this
molecule was sui generis—was not sweet or sour or bitter or salt. Ikeda decided to call
the taste umami—the Japanese word for “deliciousness.” Today, most of us
encounter glutamate on ingredient labels in the form of a salt called monosodium
glutamate, or MSG.
^*

The idea of a fifth taste was controversial
in the West until 2001, when American scientists identified a dedicated taste receptor
for glutamate on the human tongue. Now umami is generally recognized as a distinct
taste, as is the fact that, in addition to glutamate, at least two other molecules,
including the nucleotides inosine (found in fish) and guanosine (found in mushrooms)
also contribute to a perception of umami. When combined, these chemicals seem to have a
synergistic effect, dramatically intensifying the umami taste.

Like the other four tastes that have been
identified in mammals, umami is actually a discrete sense. In each case, we are born
with dedicated receptors that are wired to regions of the brain primed to respond in a
specific way. Thus no one needs to “learn” the taste of sweetness or
recognize it as positive. It is innate. Olfaction operates quite differently: Humans can
sniff out some ten thousand smells and how we respond to each of them is largely the
result of learning, individual and cultural. A smell that is appealing in one
culture—that of rotted tofu, say, to which I was treated in China—may be absolutely
disgusting in another. The difference between innate taste and learned smell is encoded
in our language, which makes clear that smell is more associative, or metaphoric, than
taste: We say something smells “
like
” something else, while we say
that something simply is sweet or bitter or whatever—no simile required.

Each of the five tastes has been selected by
evolution for its survival value. Either it guides us toward nutrients we need to
survive, or it steers us away from ingesting things that might endanger us. For example,
the taste of sweetness steers us toward particularly dense sources of energy in our
environment, which is what sugars are. Salt is an essential nutrient we have been wired
to like. Bitter happens to be how many plant toxins taste, which probably explains why
babies instinctively frown when it is introduced on their tongues. (And why pregnant
women in particular are often repelled by bitter foods.) Sour elicits an instinctive
negative reaction, too, perhaps because when food rots it generally becomes more acidic,
and rotten food is generally a risky thing to eat (stinky tofu notwithstanding). But
even though they are innate, these last two responses can be “overridden”:
many of us learn to like sour or bitter foods.

So what about the taste of umami, or
savoriness? Like salt and sugar, it evokes a universally positive response and, also
like them, it signals the presence of an essential nutrient, in this case protein.
Curiously, umami receptors have been found in the stomach as well as on the tongue.
Their purpose, presumably, is to prepare the body to digest meat, alerting it to produce
the necessary enzymes, hormones, and digestive acids. The most important chemical known
to stimulate the umami receptors is the amino acid glutamate and the nucleotides inosine
and guanosine, all of which are by-products of the breakdown of protein.