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
French wine this trend is likely to continue with further EU expansion. French law divides wine into four categories, two falling under the European Union's Table Wine category and two falling under the EU's "Quality Wines Produced in Specified Regions" (QWPSR) designation. The categories and their shares of the total French production for the 2005 vintage, excluding wine destined for Cognac, Armagnac and other brandies, were: Table wine: QWPSR: The total French production for the 2005 vintage was 43.9 million hl (plus an additional 9.4 million hl destined for various brandies), of which 28.3% was white and 71.7% was red or rosé.