What Acid Is in Vinegar?

Vinegar Chemical Composition

Acetic acid is also known as ethanoic acid.
=. Cacycle, Wikipedia Commons

What acid is in vinegar? Vinegar contains 5-10% acetic acid, one of the weak acids. Acetic acid is produced by the fermentation process used to make vinegar. Most of the remainder of the liquid is water. Vinegar may also contain sweeteners or flavorings added after the fermentation process.