Vinegar is an acidic liquid produced from the fermentation of ethanol in a process that yields its key ingredient, acetic acid (ethanoic acid). It also may come in a diluted form. The pH of table vinegar ranges from 2.4 to 3.4 (higher if diluted). The acetic acid concentration typically ranges from 4% to 8% by volume for table vinegar and up to 18% for pickling vinegar. Natural vinegars also contain small amounts of tartaric acid, citric acid, and other acids. Vinegar has been used since ancient times and is an important element in European, Asian, and other cuisines.
One hundred grams of a 5% solution of acetic acid contains 76 kJ (18 kilocalories) of food energy.
The word “vinegar” derives from the Old French word “vinaigre” meaning “sour wine“.