Fermentation is classically defined as the microbiological conversion, in the absence of oxygen, of sugars to alcohol or lactic acid. By the enzymatic conversion of sugars to alcohol, the microorganisms gain biochemical energy (ATP). biology.clc.uc.edu/Courses/Bio104/cellresp.htm Fermentation is used in many commercial food processes, including the making of sauerkraut, yogurt, wines and beers. Certain bacteria and fungi are capable of causing fermentation to occur in the absence of oxygen. Louis Pasteur is the first scientist to adequately explain the process of fermentation in 1856 when he observed lactic acid fermentation where there should have been alcohol fementation. http://www.famous-scientists.net/Louis-Pasteur.html Some industrial processes are called fermentation which are aerobic (conducted in the presence of oxygen) and would be more correctly be termed oxidative processes. http://www.angelfire.com/al/aloysius/fermentation.html

Fruits, grains, milk, and other organic substances naturally undergo fermentation during spoilage, a phenomenon which cavemen no doubt observed. Development of alcoholic drinks probably came into being not long after the development of agriculture.

In Mesopotamia, 4000-2600 BCE, wines and beers were known to be produced. Wine production was regulated by government officials and jars were officially sealed. In Mesopotamia, beers were frequently made and sold by women. The Code of Hammurambi, believed to have been developed in 1780 BCE by the King Hammurabi included regulations of the sale price of beer and its minimum alcohol content. There were also warnings prohibiting talk of sedition in the taverns of the brewer-women. http://www.fordham.edu/halsall/ancient/hamcode.html

There are two main types of industrial fermentation processes, batch fermentations and continuous fermentations. In batch fermentations, sterile growth medium is inoculated with the microorganisms and no additional growth medium is added. In continuous fermentations, growth medium is added to the fermenting medium to sustain the fermentation process. Fermentation occurs by the production of cellular enzymic reactions instead of chemical reactions aided by inanimate catalysts, sometimes operating at elevated temperature and pressure.