The colourless liquid (also acetic acid, ethanoic acid, glacial acetic acid, ethanoic acid) is one of the most common organic compounds in food. In the form of vinegar, it was the earliest of all acids to be discovered and was already well known to the Egyptians, Babylonians and Chinese in ancient times. Undiluted acetic acid is highly corrosive to the skin. It is relatively easy to recognise by the characteristic smell of vinegar, which is particularly noticeable when diluted. The taste is still pronounced even after extensive dilution acid. It is the most common volatile acid in wine. Healthy wines have a content of 0.15 to 0.5 g/l, particularly sensitive tasters object to a wine from 0.6 to 0.7 g/l. This indicates a wine with a high acidity. Above this amount, this indicates spoilage or the acetic souring, which is considered a serious wine defect.
Acetic acid is formed during fermentation by acetobacter (acetic acid bacteria) by oxidising alcohol via the intermediate product acetaldehyde. This is also known colloquially as acetic acid fermentation. However, this is not a fermentation, but an oxidative metabolic process or a so-called fermentation. Acetic acid bacteria can also get into the grape must with grape material already infected with it. The reaction of acetic acid with alcohol during fermentation also produces ethyl ac etate, which in excessive quantities can lead to the wine defect uhuton (typical acetone odour). Another aromatic compound is acetic acid isoamyl ester. The total amount of all volatile acids contained in wine is indicated as acetic acid. Depending on the type of wine, different maximum limits apply: