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 we know today. In 1935, numerous laws were passed to control the quality of French wine. They established the Appellation d'origine contrôlée system, which is governed by a powerful oversight board (Institut national des appellations d'origine, INAO). Consequently, France has one of the oldest systems for protected designation of origin for wine in the world, and strict laws concerning winemaking and production. Many other European systems are modelled after it. The word "appellation" has been put to use by other countries, sometimes in a much looser meaning. As European Union wine laws have been modelled after those of the French,