Refers to the chemical element used as a reducing and sterilising agent in viticulture and vinification, and that is available in solid, liquid and gaseous forms. In winemaking, sulphur in the form of sulphur dioxide (SO2) and sulphurous acid (H2SO3) are the required chemical aids. There is a maximum legally permitted restriction as well as a chemical analysis for the contents of free and bound sulphur dioxide and total sulphur.