Used as an antioxidant and preservative in wine. Can also be used as a sanitizer in wine making. This sodium based sulphite is most often used as a sanitizer. Fifty grams makes 1 gallon of solution. Replace with fresh material at least every other year and keep in a dry place.

Metabisulphite is available as a sodium salt or a potassium salt (potassium is considered healthier than a sodium when added to wine).