Cooked: A Natural History of Transformation (33 page)

Wheat’s own ancestors couldn’t
rise, either. Einkorn, the earliest known form of wheat, has been cultivated in
southeastern Turkey for nearly ten thousand years, but eaten mostly as a porridge or
brewed as beer. It has too much gliadin and not enough glutenin to trap fermentation
gases. The ancestry of bread wheat is tangled and still a subject of botanical debate,
but it took thousands of years of accidental crosses and mutations before a
civilization-altering curiosity showed up in a farmer’s field somewhere in the
Fertile Crescent: a stalk of wheat with big fat seeds that just happened to contain the
proteins gliadin and glutenin in just the right proportions. Gluten, and with it the
possibility of leavened bread, had come into the world.
^*

What had been one edible grass among many
became the imperial grass, spreading from the Fertile Crescent of the Middle East to
Europe by 3000 B.C., to Asia two thousand years later, and then, soon after 1492, to
both continents of the New World. Bread wheat spread because people liked to eat bread,
but also because of its central place in the Christian liturgy; priests needed bread to
give communion, and in the New World would plant it expressly for that purpose.
^†
The
only continent where wheat had not made significant inroads until
well into the twentieth century was Africa. But after World War II the United States
began giving food aid to Africa in the form of wheat, and then promoted its consumption
in cultures where it had never before been eaten. It caught on, completing the
plant’s global triumph.

Today, wheat is planted more widely than any
other single crop, waving its golden seed heads over more than 550 million acres
worldwide; there is no month of the year when wheat is not being harvested somewhere in
the world. It is true that, by weight, the world’s farmers produce more corn than
wheat, but most of that crop ends up in the stomachs of animals or the gas tanks of
automobiles (in the form of ethanol). As a food for humans, no crop is more important
than wheat. (Rice comes second.) Worldwide, wheat flour accounts for a fifth of the
calories in the human diet. And that’s low by historical standards: For most of
European history, bread represented more than half the calories in the diet of the
peasantry and the urban poor, according to French historian Fernand Braudel.

When you consider that other cereal crops
produce more calories per acre (corn, rice) and others are easier to grow (corn, barley,
rye) and still others are more nutritious (quinoa), triticum’s triumph appears
even more unlikely and impressive. The secret of wheat’s success? Gluten. Which is
another way of saying, the human love of leavened bread. Yet to put it that way is not
to have found a case-closing answer so much as another question. Because what in the
world is so wonderful about aerated porridge?

An hour into the bulk fermentation, the dough
already felt slightly different to the touch—still flabby but slightly less yielding,
and
maybe a little lighter. Robertson recommends “turning”
the dough in a container rather than kneading it on a flat surface—nearly impossible
anyway with a dough this wet. A turn involves reaching your fingers down along the
inside wall of the bowl, lifting the mass of dough up from the bottom, and then folding
it over the top; repeat the move three or four times as you rotate the bowl with your
other hand, so each quadrant gets at least one fold. That’s one complete turn.
(Wetting your fingers helps keep the dough from sticking to them.) Robertson advises a
complete turn every half hour to start, and then with diminishing frequency, and a
gentler touch, as the dough begins to billow with air. The folds help to exercise and so
strengthen the gluten, while trapping a certain amount of ambient air in the dough—each
fold creating minuscule pockets that will later balloon with carbon dioxide and
ethanol.

By the third or fourth turn, the character
of the dough has changed substantially. No longer clinging to the sides of the bowl, it
has cohered into a distinct mass and developed what feels like muscle tone. When you
pull it upward for a fold, it stretches without tearing and then pulls back down. The
dough now feels less like clay than living flesh, something in possession of will,
seemingly, and an identity. It’s also begun to smell yeasty, and what was
tasteless before is now sweet on the tongue.

Nowadays, I usually get some writing done
during bulk fermentation. The intervals between turns are just right for getting up from
my desk to take a break, and the process is sufficiently forgiving in the event I get so
absorbed in my work that I miss a turn. The dough is largely developing itself—or,
rather, my sourdough culture is developing the dough while I develop something else,
like this chapter. As I’ve heard some bakers say, baking takes a lot of time, but
for the most part it’s not
your
time.

As a means of processing a raw foodstuff, a
sourdough fermentation is a wonder of nature and culture, an example of an ancient
vernacular “technology” the ingenuity of which science is just now coming to
appreciate. “You could not survive on wheat flour,” Bruce German, the food
chemist at UC Davis, told me, “but you can survive on bread.” The reason you
can is largely due to the work of these microbes going about their unseen lives. And
though modern food science can simulate many of their effects in commercial bread
production, by using commercial yeasts and other leavening agents, sweeteners,
preservatives, and dough conditioners, it still can’t do everything a sourdough
culture can do to render grass seeds nourishing to humans.

The waste products of the various microbes
are the key to this transformation. Carbon dioxide gases produced by both the yeasts and
bacteria are what leaven the bread, while the ethanol excreted by the yeasts contributes
aromas. The organic acids produced by the lactobacilli have a whole range of crucial
effects: They contribute flavor, strengthen the dough, and, perhaps most important, help
to activate various enzymes already present in the seed.

Think of a seed as a well-stocked pantry for
the future plant: Energy, amino acids, and minerals are stored there in the form of
stable, hard-to-access molecules called polymers. The various enzymes are molecular keys
that unlock the pantry by breaking down the various polymers so that the developing
embryo will have something to eat in the period before it puts down roots. But the seed
can also be tricked into unlocking all that sequestered food for the microbes in the
starter and, in turn, for us.

The acids produced by sourdough bacteria
rouse the sleeping enzymes and put them to work. Amylase attacks the complex
carbohydrates, breaking the tightly wound (and tasteless) balls of
yarn that starches resemble into shorter, more accessible snippets of sugar. The
proteases break the long protein chains into their amino acid building blocks. These
sugars and amino acids contribute to the flavor and beauty of the bread, by feeding the
chemical reactions (both Maillard and caramelization) that, in the oven, will brown the
crust. They also feed the yeasts, thereby helping to make the bread airier. But airiness
in bread does more than make it attractive. The air pockets provide a place for steam to
form, and since steam gets considerably hotter than water (which never exceeds the
boiling point), it helps to more completely cook (or “gelatinize”) the
starches, rendering them both tastier and more digestible.

Sourdough fermentation also partially breaks
down gluten, making it easier to digest and, according to some recent research from
Italy (a nation of wheat eaters with high rates of celiac disease and gluten
intolerance), destroying at least some of the peptides thought to be responsible for
gluten intolerance. Some researchers attribute the increase in gluten intolerance and
celiac disease to the fact that modern breads no longer receive a lengthy fermentation.
The organic acids produced by the sourdough culture also seem to slow our bodies’
absorption of the sugars in white flour, reducing the dangerous spikes of insulin that
refined carbohydrates can cause. (Put another way, a sourdough bread will have a lower
“glycemic index” than a bread leavened with yeast.) Lastly, the acids
activate an enzyme called phytase, which unlocks many of the minerals that, in a seed,
have been carefully locked up (or “chelated”) for the eventual use of the
germinating plant.

To learn about the many beneficial
transformations taking place in my lump of dough during its bulk fermentation is to gain
a deeper appreciation for the genius of human culture—for having “figured
out” how to process grass this way—but equally for the ingenuity of
the microbial culture that actually does the most important work of
bread making. The dance of mutual exploitation that these two cultures have performed
for six thousand years now has served both of us well, and required no conscious
awareness on our part beyond the recognition and remembering of what seemed to work.
Much like a soil, which it in some ways resembles, a sourdough culture can be nurtured
and cultivated without having to be understood. But now that science has given us a
belated understanding of all that a sourdough fermentation can do to render grass seed
so nourishing and tasty, we can only marvel that we would have so blithely abandoned it,
for no good reason other than our impatience—and, perhaps, our desire to control rather
than to dance or surf.

I decided the bulk fermentation was complete
after about six hours, when my dough was soft and billowy and showed more interest in
clinging to itself than to me or its container. What had felt reluctant in my hands now
felt willing and lively. Fat marbles of gas had formed directly beneath its snowy skin,
and the dough gave off a nice, yeasty aroma tinged with alcohol and vinegar. I sampled a
pinch of dough; it tasted sweet and slightly acidic. To let it go any longer was to risk
too sour a bread, so I decided the time had come to move on to the next step: shaping
the dough into loaves.

Here is where my difficulties began. The
book said to scoop the mass of dough onto a floured work surface, divide it into two
pieces with a bench knife (basically a big plastic knife), and shape each piece of the
still sticky but now perky mass into a globe, or
boule
, the French word for a
round country loaf. (Also the root of the French word for baker,
boulanger
.)
The dough was so wet that this proved difficult and messy, but after dusting my hands
and the cutting board and every
other surface in the kitchen with
white flour, I was able to coax the dough into a pair of vaguely globular shapes. The
instructions said to take a round of dough in both hands and rotate it while maintaining
contact with the work surface; the bottom of the dough should cling, slightly, to the
countertop, thereby creating some tension in the surface of the sphere as it takes
shape. At first my globe resembled an attractive white buttock with some muscle tone,
but it soon relaxed into something considerably more flaccid and pancakelike.