Acetic acid is an organic compound with the chemical formula CH₃COOH. It is a colourless liquid that when undiluted is also called glacial acetic acid. Acetic acid is the main component ofvinegar (apart from water), and has a distinctive sour taste and pungent smell. Although it is classified as aweak acid, concentrated acetic acid is corrosive, and attacks the skin.

Acetic acid is one of the simplestcarboxylic acids. It is an importantchemical reagent and industrial chemical, mainly used in the production of cellulose acetate mainly forphotographic film and polyvinyl acetatefor wood glue, as well as synthetic fibres and fabrics. In households, diluted acetic acid is often used indescaling agents. In the food industry, acetic acid is used under the food additive code E260 as an acidity regulator and as a condiment.

The global demand of acetic acid is around 6.5 million tonnes per year (Mt/a), of which approximately 1.5 Mt/a is met by recycling; the remainder is manufactured from petrochemicalfeedstock.^[2] As a chemical reagent, biological sources of acetic acid are of interest but generally uncompetitive. Vinegar can be dilute acetic acid produced by fermentation.