A common spoilage in wine is the development of a vinegar character from the production of the volatile compound acetic acid. Acetic acid is a normal end product of fermentation but is usually produced in quantities well below its sensory threshold. Spoilage yeast such as Brettanomyces or bacteria like Acetobacter are the culprit for excessive formation. This flaw tends to develop either early in wine production prior to the onset of fermentation, or after fermentation during ageing. Proper sanitation, judicious use of SO2, proper storage during ageing, and diligence in maintaining quality will help prevent spoilages that result in volatile acid character.
