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
Pinard (wine) Pinard (wine) Pinard is a French term for wine (particularly red wine), popularized as the label for the ration of wine issued to French troops during the First World War. The term became wrapped up in the public conception of the "poilu" ("hairy one", the typical French foot soldier) and his loved "pinard", joined in a "cult of wine". Although the definite answer is unclear, a contemporary work defined the term's origin thus: Thus, for instance, "pinard", wine, was all but unknown in Paris before the war, yet it is now perhaps the most famous word in the whole soldier