We often romanticize wine. We think of it as a product made when humans gently coax nature into making drinkable art. While true, that image contrasts with that of wine production as a business. Whether a winery is family-run or a multinational giant, grapes are the raw material and wine the finished product. Though less poetic, this perspective can help us understand the decisions all winemakers make to ensure their wine is successful. Using sulphur is one such decision. Often included as a preventative measure, but sometimes as a fix, using sulphur in wine production is, for many grape growers and winemakers, less a choice than a requirement.
Sulphur is a naturally abundant non-metallic element that, while essential for life, is also an antioxidant and a germicide. The term sulphite that appears on wine labels as a warning is a catch-all term for the many forms sulphur can take. Because of its effectiveness in controlling oxidation and microbial growth, sulphur use in low concentrations has become widespread throughout the food and beverage industries. When it comes to wine, it has major roles in the vineyard and the winery.
In the vineyard, sulphur has, since the mid-19th Century, become a common treatment against the fungal disease known as oidium. At that time, growers discovered dusting the vines with powdered sulphur in the summer months was an effective preventative measure. As an alternative to chemical and biochemical agents, this form of sulphur application continues to be common practice in many wine-producing regions and is even sanctioned by organic grape growers.
Sulphur can also be used in the winery. When burned, it becomes a gas, sulphur dioxide. Many wineries use a traditional method in which they suspend lit sulphur wicks inside casks and barrels to disinfect them against the bacteria that cause acetic acid. Beyond sterilizing equipment, sulphur dioxide can also be applied directly to grapes and wine to prevent oxidation, bacterial spoilage and undesired fermentations. When skilfully used, sulphur dioxide delivers wines with no detectable negative aromas. When used haphazardly, it can remain in the wine in excessive amounts and emit an unpleasant and distracting odour of burnt matchsticks. Decanting and aeration typically lessen the aroma’s potency.
Excessive sulphur dioxide can also be changed by fermentation into hydrogen sulphide, which smells of rotten eggs. If left untreated, hydrogen sulfide can further react with other chemicals present in the wine to create more complex sulphur compounds called mercaptans. Mercaptans vary in their offensive aromas from burnt rubber to rancid garlic, and taste bitter and astringent. At this point, the wine is essentially beyond help.
Beyond displeasing aromas and flavours, sulphites are considered one of the 10 priority food allergens. While sulphites don’t trigger a true allergic reaction, individuals with sensitivity to sulphur may experience a reaction similar to a food allergy. In particular, those who have asthma are at a higher risk.
While the use of sulphur dioxide is very common, some winemakers eschew its practice. For instance, those who produce “vin nature” would either not use it at all, or only in very small quantities when bottling white wines. For those who are sensitive or wish to avoid sulphur, these vin natures and also organic and biodynamic wines are often the best option to avoid a reaction. Beyond that, red wines typically have lower amounts of sulphites as they naturally contain antioxidants acquired from contact with the grape skins during fermentation. White wines usually have more sulphites and sweet wines tend to have the highest level.
The 2012 Triomphe Chardonnay from Southbrook, Canada’s first biodynamic winery, is a big, delicious Chardonnay available from Vintages for $22.95. An organic red option is Punset’s excellent 2008 Barbaresco from the Piedmont region of Italy. It provides dense flavours and structure and is priced at $52.95 at Vintages.
Pieter Van den Weghe is general manager and wine director at Beckta dining & wine.