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
Fortified wine da Fonseca, the founder of the oldest table wine company in Portugal dating back to 1834. Port wine (also known simply as Port) is a fortified wine from the Douro Valley in the northern provinces of Portugal. It is typically a sweet red wine, but also comes in dry, semi-dry and white varieties. Sherry is a fortified wine made from white grapes that are grown near the town of Jerez, Spain. The word "sherry" itself is an anglicisation of Jerez. In earlier times, sherry was known as "sack" (from the Spanish "saca", meaning "a removal from the solera"). In the