The Essential Book of Fermentation (4 page)

As we make our fermented foods, let’s realize that the process we are working with is the very engine of life. Pay attention to its transformative power and imbibe its goodness with thanks. An example of this transformative power is that fermented foods improve digestion. That’s because fermentation is, in one sense, the predigestion of food, arrested as the food becomes more nutritious and better tasting, but before the digestion proceeds to decomposition. People who are lactose intolerant, for instance, can sometimes eat yogurt. That’s because lactose, the compound that people can’t tolerate, is predigested by enzymes produced by microbes in the yogurt. The action of the microbes that cause predigestion is arrested by the refrigerator. The cold conditions in a fridge don’t stop the microbes completely—freezing does that—but it slows them enough for our food to stay safe and tasty much longer than if it were sitting out on the counter. The microbes that make kefir, for example, work twice as fast at 85ºF as they do at 70ºF.

Without decomposition, we’d be slogging through millions of years of dead plants and animals piled way up over our heads.

As fermentation progresses, it becomes central to the decomposition of organic matter. Decomposition is nature’s janitorial function, ridding the world of old organic matter through the action of microorganisms. Without this process, we’d be slogging through millions of years of dead plants and animals piled up way over our heads. Fermentation is one of the factors in decomposition, but it’s also something central to how life works. It is nature’s all-important method of recycling nutrients through plants and animals. However, it works in tiny ways, so small that the fermentation actors are out of our sight. But given the impact of this infinitesimal world on our health and the health of the planet, these actors are worth a closer look.

If we could reduce ourselves in size by a factor of a thousand, we could see microbes and discover that they coat everything, inside and out. They are everywhere. Forest soil rich in organic matter is fairly made from them. They cover our bodies and the bodies of every other creature on earth, plant and animal. They are a part of us. They make up 90 percent of the cells and more than 99 percent of the genes and DNA in our bodies. “Don’t assume microbes are simple,” says Dimitar Sasselov, an astrobiologist at the Harvard-Smithsonian Center for Astrophysics. Paul Falkowski, a biophysicist and biologist from Rutgers, adds, “Animals are overgrown microbes. We are here to ferry microbes around the planet. Plants and animals are an afterthought of microbes.”

“We are here to ferry microbes around the planet.”

The invisible inhabitants of the microbial world rule this planet. They have been here for billions of years and are exquisitely and successfully adapted to life on earth. Try as we might to wipe them out with antibiotics, antimicrobial gels, and bactericidal soaps, all we succeed in doing is selecting for resistant strains that quickly reproduce, presenting us with super-strong versions of themselves. It’s the same reason that pesticides don’t work. They may curtail various insects’ activities in the short run, but soon new and improved versions of those insects will come storming back, able to ignore those pesticides. It’s nature’s way. She has strength in numbers, and evolves resilient populations of microbes that overcome whatever we humans, in our shortsighted attempts at control, throw at them.

As on the organic farm, the best strategy is to work with nature, not against her. If nature wins, we all win. If nature loses to our biocidal and aggressive tactics, we all lose. And so we welcome the bacteria and yeasts of nature’s invisible world into our lives. We understand what her little minions need and what they do that benefits us.

While we can’t see this minuscule world directly with the naked eye, we can see the results they produce as easily as we see the invisible wind fluttering through a field of wheat or flapping laundry on a clothesline. A vat of wine grape juice seems to boil with bubbling billows of carbon dioxide as yeast consumes sugar. A dish of flour and water set on a kitchen counter soon becomes alive with microorganisms that will happily leaven our bread. The carcass of a dead animal slowly disappears into the environment—eaten by vultures, decomposed by microbes, its bones scattered by hungry dogs or covered with a blanket of forest leaves that eventually turn to soil that buries the evidence.

ON THE HEAD OF A PIN

In the Middle Ages, theologians argued over how many angels could dance on the head of a pin. Today, we fermenters might consider how many bacteria and yeast cells could fit on that pinhead.

Figure a pinhead is about two millimeters in diameter. A micrometer is one thousandth of a millimeter, so creatures a few micrometers in size are too small to be seen with the naked eye. An average bacterium is about two micrometers long and half a micrometer wide, while yeast cells are circular and about six micrometers in diameter. So the answer to our question is that about 10,000 bacteria or 3,000 to 4,000 yeast cells can fit on the head of a pin.

If we could see the microbial world, we’d also notice that these specks of life form colonies and that the colonies form mutually beneficial or antagonistic ecologies. And these ecosystems follow the same laws that govern the ecosystems here on our macro level. As ecosystems mature, they become more diverse. As they become more diverse, they build a healthy, interconnected web of life among the participants. Eventually they reach what’s called a climax ecosystem, which changes slowly as the participants evolve. A climax ecosystem has reached its destiny and, if not disturbed, is the definition of sustainable. This is as true of a microbial ecosystem as of an old-growth forest ecosystem.

Without microbial life, the plants and animals we know in our macro world would not—could not—exist, for there would be no way for them to get nourishment. With no microorganisms to turn sunlight into sugar, to turn the nitrogen gas in the atmosphere into nitrate fertilizers, to dismantle dead organic matter and turn it into life-giving nutrients, life as we know it would be impossible.

When microbial ecosystems are diverse, strong, and healthy, the plants and animals in our macro world that depend on them partake of that health, too. Our human-level ecosystems flourish when we stop the destruction of life caused by industrial and agricultural chemicals. Health is built from the ground up—literally—and fermentation has a huge role to play in a more sensible future.

Imagine what would happen if we as a society mimicked nature’s role in turning dead organic matter into plant food. Every year in the United States, many billions of tons of clean organic waste are mixed with toxic wastes and indigestible plastics, glass, and metals and dumped into landfills. We call it waste, and its potential is certainly wasted because there is a world of nutrition in that organic waste that could be recovered. Imagine if municipalities had a collection day for clean, organic waste—no toxics and no indigestibles allowed. If this waste was fermented by microorganisms, it would enormously enrich the waste. Enzymes change starches like paper, wood, and garbage into sugars that produce alcohol when fermented. In the process, the waste becomes enriched with the bodies of the cells doing the fermenting—it’s more nutritious coming out of the fermentation than going in. Sound familiar? The resulting mass of digested waste would be high-class fertilizer. Instead of being buried in landfills where it putrefies and contaminates groundwater, the waste could enrich the soil on the farms in the food sheds surrounding our cities and the alcohol could help power our vehicles or be burned to power generators that make electricity. Even now, fermenting garbage and organic waste in the Puente Hills landfill near Los Angeles produces landfill gas, mostly methane, that’s being captured and burned to boil water to make steam to drive turbines that produce 46 megawatts of electricity that’s sold to Southern California Edison, enough to meet the power needs of nearly 70,000 homes. While this is commendable, controlling the fermentation in large vessels could yield a wide range of useful products along with electricity.

We are in the vanguard of those who know the potential of fermenting, not only in our personal lives through the probiotics we ingest, but in the potential enhancement of the health of the farmland that grows our food and supports our own health even further. This is good, environmentally sound, sustainable, organic, and positive thinking that needs translation into action. We are the people who can push to bring it about.

Let’s take a quick look at the overall process of decomposition of dead plant and animal tissue. The tiniest single-celled microbes, like any living thing, need to eat. And what they like to eat is organic matter; that is, anything that was once alive or, in the case of some microbes that cause infections, that is still alive. As microbes decompose organic matter, they tear apart old cells and turn rigid cell walls and cell contents that are often in unusable form into liquid nutrients that seep into the soil, where living plant roots absorb them and build new tissue. Where plants grow and die, season after season, the soil is enriched by this recycling method. Where plants are eaten by animals, the same process of decomposition happens, only it happens internally in the gut and the nutrients are recycled into bone and muscle and blood and all the rest of the animal’s organs. If a carnivore eats an herbivore, the nutrients are recycled once again into the tissues of the carnivore’s body. And when the carnivore dies, its body is once again recycled back into its constituent nutrients by microbes, and the wheel of life continues to turn.

That’s the big picture. Nature, in her intricate way, has assigned types of microbes different roles in this process of decomposition and recycling. Plant nutrients are classified as macronutrients—elements that plants need in quantity to grow—and micronutrients, no less important for healthy growth but needed in far fewer quantities. The macronutrients are nitrogen, phosphorus, and potassium. The following are some of the chief types of microbes assigned to these nutrients and their duties.

The Nitrogen Recyclers

Some microbes are the recyclers of nitrogen in what soil scientists call the nitrogen cycle, turning yesterday’s plants and animals into food for tomorrow’s plants and animals. All life depends on their work dismantling old organic matter. Microbiologists know about tens of thousands of these bacteria and other microbes, but there may be many thousands and maybe millions as yet undiscovered and named. Most of them fall into five overall functional classifications:

1.
Living tissue contains proteins that are composed of nitrogen-containing molecules. When tissue dies, certain microbes use the carbon and water in it as their food, while its nitrogen is a waste product of their metabolism that is converted to ammonium salts and then into ammonia.
Nitrifying bacteria
grab the nitrogen from the ammonia and link it with oxygen atoms to form soluble nitrates that plants absorb through their roots to make new living tissue.