For reasons of hygiene, these products require constant surveillance. They must be used sparingly, and only when necessary. While there is general agreement on the special properties and advantages of sulphur dioxide, it is still one of the most loathed chemicals. Over the years, wine makers have sought to replace it. The problem is that no other additive has successfully ensured the protection of the must and the wine with such a high degree of effectiveness.
Sulphur dioxide inhibits yeasts and bacteria by preventing oxidation.
As too much sulphur dioxide will create problems with hygiene and taste, its utilization must be carefully regulated by the home wine maker. Only tiny doses harmless to humans are used in wine making, but some people do suffer from allergic reactions caused by sulphur dioxide. Nevertheless, SO2 remains one of the best antiseptics known for wine. Today, because we have a better understanding of its chemistry and behavior, the use of sulphur dioxide can be kept to a strict minimum. SO2 develops in wine in two ways, free and combined.