Acetic Acid Fermentation

Appears in

Oxford Companion to Sugar and Sweets

Oxford Companion to Sugar and Sweets

By Darra Goldstein

Published 2015

  • About
Another important metabolic product of the fermentation of sugars is acetic acid, more commonly known as vinegar. Acetic acid is not metabolized directly from sugars, but rather from alcohol. Thus, the fermentation of acetic acid from sugars is a two-stage process: first, the fermentation of sugars into alcohol; then a distinct microbial process in which the alcohol is converted into acetic acid. Vinegar can be made from any fermented alcohol or solution of fermentable sugars.

The bacteria that metabolize alcohol into acetic acid are known as Acetobacter. Acetobacter are aerobic organisms that can convert alcohol into acetic acid only in the presence of oxygen. This is why alcoholic beverages are typically fermented under conditions designed to exclude air, to avoid conversion of alcohol into acetic acid. But when acetic acid is the desired outcome, a vessel with a broad surface area is used to maximize contact with oxygen.