Fermentation is one of the oldest and most inherent forms of food processing and preservation. Originally the transition of fresh foods and herbs into a fermented form was unwitting, and considered in ancestral and indigenous cultures to be the result of “good spirits” acting on the food, while food spoilage into something inedible or even toxic to the body was attributed to “bad spirits”.  Fermentation permeates every culture on earth just as the microbes that are responsible for the fermentation itself are a part of the universal human landscape.
The most basic definition of fermentation is that it is an anaerobic (oxygen-free) metabolic process in which cells (generally microbes such as yeast and bacteria) convert organic compounds (sugars) into simpler compounds (acid, alcohol, and/or gas). Put simply, fermentation is the microbial digestion of foods that gives us such historically dietary staples as bread, yogurt, beer, wine, kombucha, sauerkraut, pickles, kimchi, aged cheeses, cured meats, kefir, and vinegars to name only a few.
Prior to the advent of refrigeration and other food preservation methods such as high-temperature canning or sterilization, the various forms of fermentation were the only way to protect food from spoiling and to ensure the availability of nutrition in times of scarcity such as famine or winter. Fermentation can be induced in a number of ways, with a common requirement being the removal of oxygen that can fuel the growth of spoilage.
The production of acids through fermentation lowers the pH of the food making it undesirable for the microbes responsible for putrefaction or rotting to grow. In addition to preserving food, the production of acids through fermentation also provides nutritional benefits beyond what is found in the starting material. The first stage of protein digestion in the body is exposure of the food to the highly acidic stomach acid. When we eat alkaline food more stomach acid production is required in order to denature proteins and begin digestion, but when the foods are already sour due to lowered pH then we can digest the food more completely with less stomach acid release.
And, by allowing beneficial microbes access to the sugars and starches within the foods the process of digestion begins outside of the body. Fermented foods are already partially broken down by enzymes released from the yeast and bacteria, and again, this in turn eases the digestive effort required by our own bodies. Long proteins are fractured into smaller peptides and amino acids; sugars and starches are reduced to acids, alcohol, or gas (fizz!); and even fats within the foods are converted from intact triglycerides to free fatty acids. Minerals in food are locked within the food matrix. Fermentation unravels the matrix to make those minerals more accessible to the body.
On top of supportive acids and additional enzymes fermented foods provide scores of probiotic bacteria to the body, along with B vitamins produced by microbes during fermentation. In short, daily consumption of live, fermented foods supports digestive health from mouth to colon, along with increased nutrients such as B vitamins and bioavailable minerals.
- Buhner SH. Sacred and Herbal Healing Beers. Siris books, 1998.
- Karlin M. Mastering Fermentation. Ten Speed Press, 2013.
- Katz SE. Wild Fermentation. Chelsea Green, 2003.