fermented

Fermented describes substances that have undergone fermentation, a biochemical process in which microorganisms such as yeasts and bacteria convert sugars and other compounds into alcohol, acids, gases, or other metabolites. Fermentation occurs under low-oxygen conditions and can preserve food, modify flavor and texture, and sometimes increase digestibility or nutrient availability.

Common fermentation pathways include alcoholic fermentation, in which yeast converts sugars to ethanol and carbon dioxide; lactic acid fermentation, where lactic acid bacteria produce lactic acid; and acetic fermentation, where acetobacter oxidizes ethanol to acetic acid. Fermentation can be driven by naturally occurring microbes or by selected starter cultures.

Historically, fermentation is one of the oldest methods of food processing, used to preserve surplus harvests, enhance flavor, and detoxify certain foods. Today it ranges from traditional household preparations to industrial production of beverages, dairy products, soy products, and enzymes and bioactive compounds.

Examples of fermented foods and drinks include bread, beer, wine, yogurt, kefir, sauerkraut, kimchi, miso, tempeh, soy sauce, cheese, and fermented fish. Many of these products rely on specific microbes and conditions, producing characteristic textures, aromas, and tanginess.

Beyond food, fermentation is used commercially to produce antibiotics, enzymes, amino acids, vitamins, and biofuels. Some fermented foods contain live microbes that may offer probiotic benefits, though health effects vary. Proper hygiene and controlled conditions reduce safety risks associated with fermentation.