by Sarah West

Of all the food processing methods I know, fermentation holds the greatest allure. Baking is transformative, grilling primal. Canning and freezing create links between present and future. Chopping, slicing, salting and seasoning achieve distinct, even revelatory flavors. Marinades tenderize, eggs can do anything, sugar turns water to silk, and fats are the cook’s currency. But none of these create change that is alive.

At its most basic, fermentation is a chemical process that converts sugar into energy without the use of oxygen. We have all experienced this, whether we know it or not, the last time we went for a sprint. Human muscle cells are capable of fermenting sugar into lactic acid for brief bursts of energy otherwise known as that burning sensation in your calves. The kind of fermentation I am referring to here, however, is one facilitated by bacteria.

Alcohol fermentation is likely the most familiar of the bunch. Yeast, a form of bacteria, breaks sugar down into smaller particles, releasing alcohol along the way. Bread, unless it is sourdough, relies on a quick and controlled fermentation of the grain using isolated bacteria in the form of store-bought yeast. (Sourdough captures yeasts that exist in the air through a much slower, and perhaps more thorough, ferment.) Various methods of bacterial fermentation have been used throughout history to preserve food or unlock its nutrient potential: think cheese, miso, salami and vinegar. Lesser known in our contemporary culture, however, is lacto-fermentation, a process that harnesses lactobacillus bacteria to preserve, enrich and fundamentally transform a whole spectrum of foods.

The list of traditional foods prepared using the same basic principles is diverse. If you were raised in New York, you know of sour pickles, cucumbers fermented in salty brine to crispy and sometimes effervescent perfection. Those raised in or nearby Korean diasporas have likely tasted kimchee at some point in their lives. Ancestors of Slavic immigrants may have regularly drunk a cup of homemade kefir. Nearly all of us know the results of lacto-fermented milk in the form of yogurt, though unless the label specifically mentions “live, active cultures,” commercial yogurt is pasteurized post-fermentation and has lost its living flavor.

Growing up in Wisconsin, the first living lacto-fermented food I tasted was sauerkraut. Kraut that comes in shelf-stable jars is uninspiring stuff, fermented long ago, pasteurized and pressure canned, killing the bacteria and with it much of the flavor. One summer, sauerkraut was piled onto my bratwurst straight from a crock. The flavor was unlike anything I had tasted previously in my life—salty, sour, buttery smoothness that twisted into a yeasty tang, and something more, something full and exciting and entirely new. The whole package was a flavor so satisfyingly delicious I wanted to go back and ask for seconds, sans the brat.

For many, the taste of fermented foods takes some getting used to. It can be a powerful force in the mouth, rising up the navel passages like a herd of wild horses, activating, it seems, nearly all the taste buds at once. Yet, the flavors of fermented foods are an acquired taste only because we have, as a culture, nearly abandoned them. Wherever your family came from, your ancestors knew and appreciated the flavors of ferments. Surely they are more familiar and valuable to our species than the chemical agents we rely on now to preserve and flavor our food.

But, you ask, why should you want more (not fewer) bacteria in your food? Because not all bacteria are created equally. We have become used to viewing bacteria as transmitters of sickness. Armed with a host of antibacterial products, we clean our homes and hands of them without discretion. But many bacteria are our allies, existing within our bodies and throughout our environments in symbiosis. Lactobacilli already live naturally in our gut and so it behooves our digestive system to diversify the collection by eating lacto-fermented foods. And that is just what we know so far. Recent studies, such as one linking gut bacteria to mood enhancement profiled last September in The Economist , hint at deeper connections between microbes and consciousness.

The microbes fostered by fermentation have evolved along with our human cultures. It seems to me that the “something else” I first tasted in the sauerkraut, a dynamic flavor I feel compelled to seek out and recreate in my own kitchen, is this living component, carrying with it connections to thousands of years of my species’ evolution. It takes time to peel away from the fats and sweeteners of processed foods and begin tasting real food again. But your mouth will remember.

(Originally published in the Hillsdale Farmers’ Market newsletter, The Grapevine, September 6, 2012)