SULPHUR DIOXIDE IN WINE: the great debate

The use of sulphur dioxide as a preservative in winemaking is a contentious topic, and it elicits strong opinions from producers and wine lovers alike. Rupert Joy gives an overview of the issue, weighing the pros and cons of an SO2-free approach

- Rupert Joy

There was a time, not so long ago, when making quality wines without adding sulphur dioxide (SO²) was widely considered close to impossible, largely the preserve of mavericks. Inspired by the philosophies of natural wine guru Jules Chauvet, a small group of independent-minded producers such as Pierre Overnoy in Jura, Marcel Lapierre in Beaujolais, Gramenon in the Rhône and Frank Cornelissen in Sicily sought to relearn ways of making wine without the need to add SO².

Today, as more and more consumers seek out ‘minimal intervention’ wines and the natural wine movement becomes increasingly mainstream, so-called ‘no sulphites added’ (NSA) wine is made all over the world. But the issue remains divisive. At one end of the spectrum are figures such as Champagne’s enfant terrible Anselme Selosse, arguing that SO² ‘lobotomises wine’; at the other, Monika Christmann, former president of the International Vine & Wine Organisation (OIV), warning of deteriorating wine stability caused by a ‘downwards spiral’ in the use of SO² in winemaking.

Sulphur dioxide is naturally produced by yeasts during fermentation, so all wines contain some sulphites. The practice of adding sulphites during the winemaking process to stabilise or preserve wine goes back to at least the 18th century. Conventional producers may add SO² at different stages from harvest to bottling in order to prevent microbial spoilage of wine from unwanted bacteria and yeasts and to minimise oxidation.