For the colourless, mucous membrane-irritating, pungent smelling and acid tasting toxic gas, the designation "E220" is commonly used in the food industry within the EU and "220" in the New World. It is mainly produced during the combustion of fossil fuels containing sulphur, such as coal or petroleum products. It contributes significantly to air pollution and is the cause of acid rain. In winemaking, sulphur dioxide is used in gaseous and liquid form mainly as an oxidation inhibitor or for preservation.
The gas is produced by burning sulphur cuts, which is used in the so-called dry preservation of barrels. In the so-called wet pres ervation, the gas is introduced into the barrels filled with water. The liquid form is created by increased atmospheric pressure. When the gas combines with water (wine), a large part is converted into sulphurous acid and this is converted into sulphites by further processes. Sulphur can trigger allergic reactions in food. Therefore, if the sulphur content exceeds 10 mg/l, this must be indicated on the label, which is the case for almost all wines. See the maximum permissible values per wine type under sulphurous acid.