Potassium metabisulfite

Potassium metabisulfite (CAS 16731-55-8), also sold as potassium pyrosulfite and approved as E224, is an inorganic sulfite salt used industrially as a preservative, antioxidant, and reducing agent.

It releases sulfur dioxide upon contact with moisture or acids, making it effective for microbial control and oxidation prevention across food, beverage, and industrial applications.

In winemaking and brewing, it is the standard choice for sanitizing equipment, inhibiting wild yeast, and protecting finished products from oxidative spoilage during storage.

Food manufacturers use it to prevent enzymatic browning in dried fruits, potato products, and seafood processing. Water treatment operations rely on it to dechlorinate potable water.

It is also used for process streams before discharge or further treatment. In textile and leather processing, it functions as a bleaching and reducing agent during fabric preparation.

Potassium metabisulfite is supplied as a white crystalline powder or fine granules. Standard commercial grades include food-grade (FCC), pharmaceutical-grade (USP, BP), and technical-grade.

Purity levels typically range from 97% to 99%, with food and pharma grades carrying tighter sulfur dioxide content specifications to ensure safety and compliance for global distribution.