A common additive used to preserve and stabilize wines, ciders, and occasionally beers. When added to wine or must, it forms sulfur dioxide gas (SO2). This prevents most wild microorganisms from growing and acts as a potent antioxidant, protecting both the colour and delicate flavours of wine. Sodium sulfite solutions are also used to sanitise rinses for wine-making and beer brewing equipment.
It has identical functions but potassium metabisulfite is usually preferred as an additive because it does not contribute any dietary sodium, but sodium metabisulfite is more popular as a sanitizing rinse.
To make a sanitizing rinse for equipment, dissolve 8 teaspoons of sodium metabisulfite into 3.5 litres of water. High concentrations of sulfur dioxide gas are irritating and toxic, so use in a well-ventilated area. After applying the solution to your equipment, the items must be rinsed with clean, cold water.
To read more about Sodium Metabisulfite click here.