Acetic Acid Bacteria
Definition - What does Acetic Acid Bacteria mean?
Acetic acid bacteria, which can be found in the vinegar form of some wines, is also referred to as Volatile Acidity (VA) or vinegar taint in wine language. It is caused by a family of Acetobacteraceae bacteria consisting of ten different varieties. This bacteria is naturally found in any environment where ethanol (alcohol) is being created as a result of sugars being fermented.
Like many other acids (malic, tartaric, citric, etc), acetic acid is naturally occurring in the winemaking process, however, it is the quantity of VA in the wine that determines whether it has more or less characteristics as vinegar. If the bacteria is present, or for example, there are fruit flies in the winery carrying the acetic acid bacteria, then one of the bi-products of fermentation will be ethyl acetate (acetic acid). Using wild yeasts, which are naturally existing in the vineyards and on the grapes during harvest can also carry the acetic acid bacteria.
Preventing the acetic acid fermentation of wine can be controlled by using synthetic-approved or organic-approved yeasts and the thorough cleaning and sanitizing of equipment and the winery environment.
WineFrog explains Acetic Acid Bacteria
It is not an uncommon characteristic for a wine to carry the acetic acid bacteria or for a wine to have slight characteristics of vinegar. Many Old World wines are known for such components and characteristics that for many familiar with these wines, they would not be the same without.
However, as a general rule, existence of the acetic acid bacteria in a winery is not a desired one. Once a winery is 'contaminated' with the bacteria, it is often a great challenge to get rid of it. In order to prevent a wine from becoming vinegar or have traces of vinegar due to the fermentation of acetic acid bacteria in the process, wineries must sanitize the area.
A lot of the winemaking processes include the use of hoses, pumps and many other pieces of hardware and laboratory equipment. The cleansing and sanitation of pumps, hoses, connecting hardware and tanks will often prevent the possibility of initiating acetic acid bacteria into the winery or wine. Further cleansing of floors and other large equipment from wine spills and juice spills and remnants from harvest, which will attract fruit flies are another way to prevent the occurrence of the bacteria.