acetic

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.”

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

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.

When treated with hydrochloric or acetic acid they slowly dissolve and rhombic crystals of uric acid appear.

Crystals of calcium oxalate are insoluble in acetic acid or caustic soda.

Upon addition of acetic acid they dissolve, and rhombic plates of uric acid appear.

Let dry, apply a cover-glass, and run glacial acetic acid underneath it.

It dissolves in dilute potash, and on the addition of acetic acid is deposited in a pure state.