Fermentation - Wikipedia, the free encyclopedia "Fermentation typically refers to the conversion of sugar to alcohol using yeast. The process is often used to produce wine and beer, but fermentation is also employed in preservation to create lactic acid in sour foods such as pickled cucumbers, kimchi and yogurt. The science of fermentation is known as zymology.

In its strictest sense, fermentation (formerly called zymosis) is the anaerobic metabolic breakdown of a nutrient molecule, such as glucose, without net oxidation. Fermentation does not release all the available energy in a molecule; it merely allows glycolysis (a process that yields two ATP per glucose) to continue by replenishing reduced coenzymes. Depending on which organism it is taking place in, fermentation may yield lactate, acetic acid, ethanol, or other reduced metabolites. Yeast produces ethanol and CO2; human muscle (under anaerobic conditions) produces lactic acid.

Fermentation is also used much more broadly to refer to the bulk growth of microorganisms on a growth medium. No distinction is made between aerobic and anaerobic metabolism when the word is used in this sense.

Fermentation usually implies that the action of the microorganisms is desirable. Occasionally wines are enhanced through the process of cofermentation. When fermentation stops prior to complete conversion of sugar to alcohol, a stuck fermentation is said to have occurred."  ¶ 2:00 AM