A white crystalline powder with a pungent sulphur odour
Potassium Metabisulphate is a food preservative which preserves the natural colour of food and protects food against bacteria.
The winemaking industry uses Potassium Metabisulphate as an additive during the bottling process. When they add Potassium Metabisulphate to wine, a sulphur dioxide gas forms, which destroys microorganisms in the wine and prevents moulds and bacteria from growing inside the wine bottle.
Potassium Metabisulphate is sometimes used in the brewing industry to inhibit the growth of wild bacteria and fungi called 'stabilising'.
It is also used to neutralize chloramine that has been added to tap water at the source as a disinfectant and is used both by homebrewers and commercial brewers alike.