How vinegar is made

Vinegar is wine's second life. Bacteria turn alcohol into acid in tanks fed with air.

stations: 6
things upstream: 15
raw sources: 8
steps from the ground: 5

The short version

Vinegar is made by double fermentation. Yeast first turns sugar in grape juice, malt or grain into alcohol, then acetic acid bacteria with plenty of air turn the alcohol into acetic acid. Slow methods take months, while the submerged tank method used for cheap vinegar needs only 1 to 3 days.

Pick a sugary liquid

Makers start from fruit juice, grape must, malted grain or a plain solution of grain alcohol. Balsamic vinegar starts from grape product, malt vinegar starts from beer, and spirit vinegar begins with distilled ethanol.

Goes in
Wine grapes Ethanol Malted barley
Ferment sugar to alcohol

Yeast eats the sugars in the liquid and gives off alcohol. This first fermentation is the same one that makes wine or beer.

Goes in
Baker's yeast
Add the acid bacteria

A starter, sometimes called mother of vinegar, brings in acetic acid bacteria. Traditional makers let a slime-like mat of the bacteria float on the surface of barrels.
Bubble in air

The bacteria need oxygen to turn ethanol into acetic acid. In a submerged fermenter, air is pumped through the liquid constantly, and the fast route finishes in 1 to 3 days. Slow barrel methods take a few months up to a year.

1 to 3 days in a fast tank
Filter and standardize

The liquid is filtered to remove bacteria and solids, then diluted with water to a set strength. Vinegar typically contains from 4% to 18% acetic acid by volume.

Goes in
Water
Pasteurize and bottle

A short heat treatment stops any leftover bacteria from working. Vinegar is then bottled, and some kinds are aged in wood first.

End of the lineVinegar Next it goes into mayonnaise, ketchup, mustard and 3 more.

Worth repeating

The first documented vinegar making was by the ancient Babylonians around 3000 BCE, from dates, figs and beer.
Karl Sebastian Schuzenbach built the first large-scale industrial vinegar process in 1823, trickling alcohol over beechwood shavings.