acetic

Acetic acid bacteria are powerhouses at converting ethanol to acetic acid because it’s where they get their energy.

Yeast first need to ferment these sugars into ethanol, at which point acetic acid bacteria can take over.

In the United States, the Food and Drug Administration requires the final product to be at least four percent acetic acid by volume in order to be sold as “vinegar.”

These microorganisms take ethanol, guzzle it up for fuel, and release molecules of acetic acid directly into the developing mixture—which means vinegar is basically bacteria compost.