Food Fermentation

Food Fermentation

Fermentation has been used both for the production and preservation of various foods for thousands of years. Laborers building the Great Wall of China in the third century B.C. were fed fermented vegetables as part of their rations. Vegetables are still commonly fermented throughout Asia, but in North America, the foods most often preserved by fermentation are cucumbers, olives, and cabbage.

Carbohydrates are required for the fermentation process. Although vegetables are not usually considered sugary foods, they contain enough carbohydrates and natural bacteria for fermentation to occur. Although only the plants’ natural carbohydrates and microorganisms are needed for fermentation, salt or vinegar (acid) may be added to regulate bacterial growth.

Cucumbers can be manufactured into sweet, sour, dill, kosher dill, and other pickles by one of two methods: the longer process of fermentation, which yields brined pickles (with acid produced from the bacteria); and pickling, where acid is added in the form of vinegar, resulting in quick pickles. During the process of fermentation, a 10 percent salt solution serves as the liquid in which the cucumbers are submerged and allowed to ferment for several weeks. During this fermentation period, bacteria normally found on vegetables break down the sugar in the cucumbers. The salt penetrates the cucumbers, and the brine concentration is increased to 15 percent, except in the processing of dill pickles. Once fermented, pickles (whole or sliced) are placed in warm water, packed in glass jars, covered with a combination of vinegar, sugar, spices, and garlic, and pasteurized. It is this canning process, rather than fermentation, that preserved the pickles.