Winemakers Night at The Vines of Mendoza always offers attendees insight into the daily considerations of oenologists. One theme that consistently arises during these discussions is the consumer’s confusion over the use of sulfur in wine.

How is sulfur used in wine?

Sulfur is a natural bi-product of fermentation; therefore, even organic wines contain low levels. Further to that, it is a near impossibility to make a stable wine without additional sulfites, due to their anti-microbial and anti-oxidant properties.

When wine is slowly exposed to oxygen, like through a properly sealed cork, it develops complex flavors and aromas. However, too much oxygen too soon can destroy a wine’s fruity qualities, cause browning and color loss, or can spoil a wine altogether. Sulfur is added to help prevent these issues and to extend the life of the wine; particularly white wines which don’t contain the natural preservatives found in red wine tannins.

The anti-microbial properties of sulfur are important for controlling harmful bacteria growth. Listed below are ways that sulfur is used throughout the vinification process.

· In the vineyard:
· Sulfur is often sprayed in the vineyard in order to stop grape rot that can be caused by humidity or pests

· In the winery:
· Before starting a controlled fermentation with cultivated yeast, sulfites are added to the grape juice to rid it of harmful bacteria and unwanted wild yeast
· Can be used to stop yeast activity (fermentation)
· Stabilizes wine following malolactic fermentation (a second fermentation that converts harsh malic acid into smooth lactic acid. The process is used to soften the way a wine feels in one’s mouth)
· Winery equipment sanitization, and to prevent microbial growth in the winery

· When bottling the wine:
Prevents microbial problems from developing when the wine is in bottle

Sulfur can cause problems in the winery if mismanaged. It could cease fermentations too early, contribute a rotten egg smell or cause color loss to finished wines.

FYI: Decanting an eggy smelling wine for ten minutes will evaporate the unpleasant odor.

Is there danger in consuming sulfites?

As well as small traces in wine, sulfites are commonly used as food preservatives in foods like dried fruit, breakfast cereals and chocolate bars. This is concerning for some people as sulfites are allergens and can affect asthmatics adversely. Symptoms are rare but can include headaches, hives and cramps.

That being said, many people who attribute these symptoms to sulfur are actually suffering an allergic reaction to histamines found in red wines, largely due to the wood tannins derived during oak aging. White wines require more sulfites than red wines do. If red wine is what causes your headache, you are probably having a mild allergic reaction to oak tannins and not sulfur.

There’s no denying it. To drink wine is to drink (a small amount of) sulfites. If this concerns you, you can always try seeking out organic or biodynamic wines that may have a lesser level of sulfites. In my opinion, the benefits of sulfites in wine outweigh the cons. I love my wines fresh and lasting, sulfur ensures this along with a standard of quality in my wine that I have come to expect. Just keep an antihistamine on hand for those longer tasting sessions.

About the author: Lindsay Trivers is a Sommelier at The Vines of Mendoza, in the most recent chapter of her world-wide wine discovery tour. She has worked extensively throughout Canada, New Zealand and Australia, developing her palate and working vintages along the way. While here, in Mendoza, She will be living and reporting on life at the bodega (winery), plus happenings from the tasting room and cellar. Stay tuned to The Vines of Mendoza Blog for vintage updates, wine tips and reviews, to find out how our guests are keeping busy, and much, much more.