What is sulfur/sulfur dioxide/sulfites and why is it added during the winemaking process?
Sulfur is a naturally occurring substance, making up 0.5% of the earth’s crust. At room temperature it is a yellow, brittle, solid substance and when burnt in air, creates sulfur dioxide gas which has been used as a preservative and disinfectant since ancient times. Sulfites are also produced by micro-organisms and are present at low levels in many foods even where none has been added eg. bread. All wine contains some sulfites as a natural by-product of fermentation. During winemaking sulfur dioxide is added to inhibit oxidation and bacterial spoilage. Those winemakers who use none at all put their wines at risk of spoilage during bottling, shipment and ageing. Within the EU maximum permitted levels of total sulfur dioxide in the finished wine are 160 mg/l for dry red wines, 210 mg/l for dry white and rosé and sweet red wines, and 260 mg/l for sweet white and rosé wines. Certain very sweet wines can contain up to 400 mg/l (more sulfur is needed when there is residual sugar present to p
