Acids in wine responsible for the sour taste of vinegar. During fermentation, activity by yeast cells naturally produces a small amount of acetic acid. If the wine is exposed to oxygen, "Acetobacter" bacteria will convert the ethanol into acetic acid. This process is known as the “acetification” of wine and is the primary process behind wine degradation into vinegar. An excessive amount of acetic acid is also considered a wine fault. A taster's sensitivity to acetic acid will vary, but most people can detect excessive amounts at around 600 mg/l. Ascorbic acid, also known as vitamin C, is found in young wine grapes
Wine fruit from which they are produced combined with the word "wine" (for example, apple wine and elderberry wine) and are generically called fruit wine or country wine (not to be confused with the French term "vin de pays"). Other than the grape varieties traditionally used for wine-making, most fruits naturally lack either sufficient fermentable sugars, relatively low acidity, yeast nutrients needed to promote or maintain fermentation, or a combination of these three characteristics. This is probably one of the main reasons why wine derived from grapes has historically been more prevalent by far than other types, and why specific types