Fermentation is a natural metabolic process that produces energy by breaking down carbohydrates (such as sugars) in the absence of oxygen. It occurs in many microorganisms (such as yeasts), and the end product can be either ethyl alcohol (ethanol) or lactic acid. Energy is typically given off in the form of heat. Fermentation is important to the production of many foods and beverages, the most popular of which are bread, butter, cheese, beer, and wine.

The chemical reaction of this process was first described in 1810 by a French chemist. However, fermentation was first recognized in ancient times, when food that was stored or forgotten was found to have changed its form and taste, but remained edible. To make breads and porridges, ancient peoples farmed and stored wheat and barley, some of which fermented and formed brews. Since that time, the process of fermentation has been used worldwide. Industrial methods create huge quantities of fermented foods, as well as alcohol, which is obtained by distillation from fermented juices of fruits, grains, vegetables, and other plants.

See Also

Beers and Brews; Distilled Spirits.