Fermentation

Fermentation, in food processing, is the deliberate use of microorganisms, chiefly yeasts and bacteria, to convert the carbohydrates in a food into alcohol or organic acids in the absence of an oxidizing agent, transforming both its flavor and its keeping qualities. Fermentation underlies an enormous range of foods and drinks across virtually every culinary tradition, from bread, cheese, yogurt, sauerkraut, kimchi and miso to beer, wine and vinegar, and because the acids or alcohol it produces make an environment hostile to spoilage organisms, it is also one of humanity's oldest food preservation techniques. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/