This colourless, mucous membrane irritating, pungent smelling and sour tasting, toxic gas is commonly called "E220" in the food industry within the EU and "220" in the New World. It is mainly produced during the combustion of sulphur-containing fossil fuels 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 conservation.
The gas is produced by burning sulphur cuts, which is used in the so-called dry conservation of barrels. In the so-called wet preservation, the gas is introduced into the barrels filled with water. The liquid form is created by increased atmospheric pressure. When the gas is combined with water (wine), a large part of it is converted into sulphurous acid, which is then converted into sulphites by further processes. Sulphur can cause allergic reactions in food. For this reason, sulphur concentrations of more than 10 mg/l 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.