Agriculture Reference
In-Depth Information
There are a great many specific strains of AAB. They are
present on the surface of both healthy and damaged fruit as
well as the nectar of flowers. They are also commonly
transferred by the fruit flies that could have been attracted to
your wine-making or brewing process.
Wine is produced in anaerobic conditions, meaning that
oxygen is excluded. Vinegar, on the other hand, is produced
under aerobic conditions as the AAB require oxygen to work.
In the absence of oxygen, the bacteria go dormant.
Various strains of AAB
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are present in wine must from the
very beginning and remain in the wine even when it is
bottled.
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The primary factor that keeps it suppressed in wine
is lack of oxygen and alcohol levels that are too high for the
bacteria to process. So especially with newly-made wines, all
that is theoretically necessary to turn wine into vinegar is to
permit the entry of oxygen. In the presence of oxygen the
bacteria would quickly proliferate as a film on the surface of
the wine and turn the alcohol to acetic acid, especially if the
alcohol level is under 10%.
Beer is even more susceptible to acetification because its
lower alcohol content, lack of sulfites, and higher nutritional
content make it an attractive target.
Acetic acid bacteria are not the only bacteria that can take
hold in wine or beer, and leaving the results to chance can
result in a product that is not only unusable, but thoroughly
rotten. So for our purposes, just as a specific strain of yeast is
used to make wine, a specific strain of bacteria is used to
make vinegar. Acetic acid bacteria are commercially available
in a form called vinegar mother. Vinegar mother, also known
