Cooked: A Natural History of Transformation (45 page)

As the example of alcohol suggests, the uses
of fermentation extend well beyond preservation, though it seems likely that
preservation was humanity’s original impetus for mastering the process. (Alcohol—a
strong antiseptic—is itself an important preservative.) Archaeologists believe that,
until there were reliable methods to preserve food, humanity could not have moved from
hunting and gathering to a more settled, agricultural pattern of life. Fermentation
(along with other preservation techniques, such as salting, smoking, and drying)
provided a critical measure of food security, allowing agriculturists to survive the
long months between harvests and to withstand the inevitable crop failures. Though, as I
would discover when I started to brew beer (because brewers can
always
be
counted on to mention it), there is a school of archaeological thought that contends
that the reason humanity turned to agriculture was to secure a more reliable supply of
alcohol, not food. Either way, the
mastery of fermentation and the
advent of agriculture (and civilization in turn) appear to go hand in hand.

As so often happens, the original purpose of
an invention or adaptation doesn’t turn out to be the ultimate or even highest use
to which it is put. Humans soon recognized that fermenting various foodstuffs did a lot
more than extend their shelf life, important as that was. Fermenting the juices of fruit
not only sterilized the beverage, but also turned it into a powerful intoxicant. A great
many foodstuffs become significantly more nutritious after fermentation. In some cases,
the process creates entirely new nutrients—several B vitamins are synthesized in the
fermentation of beer, soy sauce, and various grains. Natto, the slimy odiferous ferment
of soybeans beloved by the Japanese, produces a unique therapeutic compound called
nattokinase. Many grain ferments yield important amino acids, such as lysine. Sauerkraut
contains breakdown products believed to fight cancer, including isothiocyanates such as
sulforaphane. (It also contains goodly amounts of vitamin C: Captain Cook kept his crew
free from scurvy during a twenty-seven-month journey by forcing them to eat sauerkraut.)
As I learned when I was baking bread, the fermentation process renders grain more
nutritious by breaking down chemical compounds that interfere with nutrient absorption,
such as phytate. Fermentation also breaks down toxic compounds in certain plants. That
shark I tasted in Iceland? It would have sickened me (well, even more than it did) had
it
not
been fermented. This particular species of shark has no kidneys, so
toxic levels of uric acid accumulate in its flesh; the fermentation renders it harmless.
Oxalic acid, another antinutrient, found in certain vegetables, is also broken down
during fermentation.

To ferment food is to predigest it, in
effect, breaking long chains of proteins, fats, and carbohydrates our bodies might not
be able to make good use of into simpler, safer compounds that they can. Think of the
kraut crock as a burbling auxiliary stomach, doing much of the
work of
digestion before your body has to. As with cooking, it offers your body an energy
savings. Unlike cooking, however, the energy required to ferment food does not need to
come from burning wood or fossil fuel. It is self-generated, by the metabolism of
microbes breaking down the substrate. Fermentation can easily be done off the grid, a
quality that commends it to the enviros, anarchists, and peak-oil types who help make up
the subculture. “The historical bubble of refrigeration may not last,” Katz
likes to point out. When that particular bubble bursts, you’re going to want to
know people like Sandor Katz and microbes like
L. plantarum
.

Fermenting foods also intensifies their
flavors, a particular boon to agricultural humans. The advent of agriculture
dramatically narrowed the human diet, in many cases down to a small handful of bland
staples, most of them carbohydrates. All the year long, fermented foods allowed people
to enliven a monotonous diet with strong flavors, while supplementing it with vitamins,
minerals, and phytochemicals that staple foods often lack.

People tend to feel very strongly about the
flavors of fermentation, one way or the other. “Between fresh and rotten,”
Katz has written, “there is a creative space in which some of the most compelling
flavors arise.” In the same way that the process of ripening fruits imbues them
with deeper, richer flavors and scents, many other foods acquire powerful new sensory
qualities just as they begin to decompose. Why should this be? Perhaps for the same
reason that our taste buds respond more strongly to simple sugars than to complex
carbohydrates, or to amino acids rather than long protein chains. We’ve evolved
specific taste receptors for these basic molecular building blocks (umami) and simple
packets of energy (sweetness), so respond favorably to foods that have been broken down
to those indispensable elements, whether by cooking or fermentation.

Yet many of the flavor molecules created by
fermentation are not
so simple or universal in their appeal. Could it
be that, like ripening fruits, the microbes that decompose foods produce powerfully
aromatic compounds for their own purposes? The reason fruits produce strong scents and
flavors when ripe is to attract animals that can transport their seeds. The microbes
that rot fruit or other foods also emit signaling chemicals. Some are designed to repel
competitors. But others are attractants. Like the seeds of plants, fermentation microbes
sometimes need help with transportation, especially after they’ve exhausted a food
source. Some scientists believe that bacteria and fungi produce their own taxi-hailing
scent compounds, in order to attract the insects and other animals they need to
transport them to the next feast of putrefaction.

What’s curious is how culturally
specific so many of the flavors of fermentation turn out to be. Unlike sweetness or
umami, these are not the kinds of simple flavors humans are hardwired to like. To the
contrary, these are “acquired tastes,” by which we mean that to enjoy them
we often must overcome a hardwired aversion, something it usually takes the force of
culture, and probably repeated exposure as a child, to achieve. The most common term
children and adults alike will use to describe the fermented foods of another culture is
some variation on the word “rotten.” A wrinkle of the nose is how we react
to both rottenness and foreignness. Many of these foods occupy a biological frontier—on
the edge of decomposition—that turns out to be a well-patrolled cultural frontier as
well.

Considered as a method, or set of methods,
for food processing—for turning the stuff of nature into safe, nutritious, durable, and
delicious things to eat—the ancient arts of fermentation have yet to be improved on. For
what has modern food science given us that can compare? Vacuum-sealed cans. Frozen
foods. Microwavable entrées. Mock meats made from soy. Baby formula. Irradiated food.
Vitamin-fortified breakfast cereal in colors. Energy bars. Powdered Jell-O.
Marshmallow fluff. Cryovacking. Freeze-drying. Artificial sweeteners.
Artificial sweeteners with fiber. Margarine. High-fructose corn syrup. Low-fat and
no-fat cheese. Quorn. Cake mix. Frozen peanut butter and jelly sandwiches. The countless
simulations of real foods and real flavors that line the center aisles of the
supermarket. Stack any of these inventions up against such achievements as wine or beer,
against cheese, against chocolate, soy sauce, coffee, yogurt, cured olives, vinegar,
pickled vegetables of all kinds, cured meats, and the conclusion is inescapable:
Thousands of years on, we still haven’t discovered techniques for processing food
as powerful, versatile, safe, or nutritious as microbial fermentation.

And yet these latter-day industrial methods
of food preservation and processing have pushed most live-culture foods out of our diet.
Yogurt is the exception that proves the rule, which is that very few of our foods any
longer contain living bacteria or fungi. Vegetables are far more likely to be canned or
frozen (or eaten fresh) than pickled. Meats are cured with chemicals rather than
microbes and salt. Bread is still leavened with yeast, but seldom with a wild culture.
Even the sauerkraut and kimchi are now pasteurized and vacuum packed—their cultures
killed off long before the jar hits the supermarket shelf. These days most pickles are
no longer truly pickled: They’re soured with pasteurized vinegar, no lactobacilli
involved. Open virtually any modern recipe book for putting up or pickling food and you
will be hard pressed to find a recipe for lactofermentation: What once was pickling has
been reduced to marinating in vinegar. And though it’s true that vinegar is itself
the product of fermentation, it is frequently pasteurized, a finished, lifeless product,
and far too acidic to support most live cultures.

The modern food industry has a problem with
bacteria, which it works assiduously to expunge from everything it sells, except for the
yogurt. Wild fermentation is probably a little too wild for the
supermarket, which has become yet another sterile battlefield in the war on bacteria.
Worries about food safety are very real, of course, which is why it’s probably
easier for the industry to stand staunchly behind Pasteur than to try to tell a more
nuanced story about good and bad bugs in your food. With the result that live-culture
foods, which used to make up a large part of the human diet, have been relegated to the
handful of artisanal producers and do-it-yourselfers signing up for Sandor Katz’s
“cultural revival.”

This might not matter to much of anyone but
a confirmed Slow Foodie, eager to save and sample endangered food traditions, except for
one notable fact: Medical researchers are coming around to the startling conclusion
that, in order to be healthy, people need
more
exposure to microbes, not less;
and that one of the problems with the so-called Western diet—besides all the refined
carbohydrates and fats and novel chemicals in it—is the absence from it of live-culture
foods. The theory is that these foods have a crucial role to play in nourishing the vast
community of microbes living inside us, which in turn plays a much larger role in our
overall health and well-being than we ever realized. Bacteria-free food may be making us
sick.

My first solo expedition into the wilds of
the post-Pasteurian world came last summer, when I tested a few of Sandor Katz’s
pickling recipes at home. I decided to begin my education with vegetable ferments
because they seemed the easiest and, which is important, the safest. No less an
authority than Steinkraus had written that the safety record of fermented vegetables was
very good even when “the foods are manufactured by people without training in
microbiology or
chemistry in unhygienic, contaminated
environments.” (That would be me.) One USDA scientist went so far as to claim that
there has never been a documented case of food-borne illness from eating fermented
vegetables.

Suitably reassured, I bought a case of
quart-sized Mason jars at the hardware store. I did not sterilize them, just rinsed them
out with some hot tap water. I also ordered online a 7.5-liter German sauerkraut crock.
The perimeter of this ceramic crock has a deep circular well into which the lid fits;
filling this moat with an inch or two of water creates an airlock that prevents oxygen
from getting in while allowing the carbon dioxide emitted during fermentation to bubble
out. Note: I discovered when it arrived that 7.5 liters is a much bigger crock than
anyone needs, unless you’re planning to feed a small German village. It took no
fewer than six large heads of cabbage to fill my crock. That represents easily a few
years’ worth of sauerkraut in my house.

Fermentation vessels at the ready, I paid a
visit to the farmers’ market and bought a bunch of pickle-able vegetables:
cabbages of course (both Napa and regular), cucumbers, carrots, cauliflower, sweet and
hot peppers, beets, radishes, turnips, etc. At the supermarket, I loaded up on bulbs of
garlic, ginger roots, and various pickling spices—juniper berries; dill, coriander, and
caraway seeds; star anise; and black pepper—and a big box of sea salt.

According to Katz, there are two basic
approaches to fermenting vegetables: leafy ones, like cabbage, are best fermented in
their own juices, whereas others require the addition of a brine to keep them fully
submerged in liquid. The saltiness of the brine is a matter of personal preference, but
several of the sources I consulted recommended 5 percent, so I started with that. I
dissolved the salt in a pot of hot water (roughly an ounce of salt for every three cups
of water),
to which I added various combinations of spices.
^*
While the mixture cooled on the stovetop, I packed the vegetables into a Mason jar
(usually with cloves of garlic, sometimes with sliced ginger as well) and then poured
the brine over them. Katz had said the vegetables should be completely submerged, but
invariably some insist on floating to the top, exposing themselves to oxygen—and the
possibility of rot. I tried a variety of tricks to force them back underwater, including
a saucer, some Ping-Pong balls, a plastic bag filled with pebbles, and some weighted
grape leaves. I had read that grape leaves, which contain tannins, help keep the
vegetables crisp by suppressing certain fungi. (Oak, cherry, or horseradish leaves, do
the same thing.)