Vinegar Production

White vinegar for domestic consumption is a colourless liquid containing 4-7% by volume of acetic acid in aqueous solution, although common industrial applications may contain up to 20% by volume. The most common process is a double fermentation where yeast is used to converts simple sugars to ethanol and acetic acid bacteria are used to convert ethanol to acetic acid.

Black vinegar is a dark-coloured vinegar traditionally used in Chinese cuisine. Like white vinegar, it is produced in a double fermentation. The starting material is typically glutinous rice, although many other cereals and their brans are also used. The Maillard reaction causes the brown colouration, where carbohydrates react with amino acids . A description of the steps involved in the production is given in paper below.