Those Sulfites In Wine? Not Evil!

Just about every bottle of wine you've ever purchased or drunk in the U.S. has had two words on the back label: "contains sulfites." The warning sounds ominous. But sulfites are naturally occurring compounds that plants produce to protect themselves from microbial infection. In winemaking, sulfur dioxide (or SO2) is released during fermentation. Winemakers have been adding sulfur to wine for hundreds (and possibly thousands) of years to help prevent it from spoiling. So, why do sulfites sound so scary?

First off, sulfites sound like sulfates, which are a whole other can of chemical compounds. The two words might sound similar, but where sulfites are compounds that contain sulfur, a natural preservative, sulfates are harsh mineral salts that contain sulfur. In some cases, sulfates are harmful residues derived from industrial waste that can contaminate drinking water. That's one reason sulfites can put people off.

Another reason, as Professor Andrew Waterhouse, a wine chemist at U.C. Davis, points out, is that it's the only warning that appears on most bottles of wine. So, maybe it's just psychological. However, for years, people have reported that sulfites can cause headaches, even though no hard data supporting the claim exists. Of course, there are many compounds in wine that can contribute to headaches – alcohol being the most obvious. But Dr. Waterhouse says that the anecdotal evidence suggesting that sulfites can cause headaches is worth noting.

"There is no published data about the effects of sulfites in wine because no one has studied it yet," he explains. "The Center for Disease Control probably has more pressing issues than researching what in wine causes headaches, but I tell people [who say sulfites cause them headaches] to try eating dried apricots [which can contain 10 times more sulfites than wine] and they say that, yes, they've gotten headaches from that, too."

Just about every conventional winemaker adds sulfites to his wine to keep it fresh and stable in the bottle. Many go as far as to maintain that good quality wine cannot be made without them. Specific flavors associated with oxidation or microbial growth considered to be defects have been reported in wines made without added sulfites. But a few rogue winemakers, mostly in Europe, see things differently. They add no sulfites to their wines, or very few sulfites, claiming that this makes for a purer expression of the grape and terroir. Dr. Waterhouse says that making wine this way is possible; it just requires much more care and attention and it may have a shorter shelf life.

Marie Zusslin started experimenting with withholding sulfur from her wines for the 2005 vintage. She and her husband, Christophe Ehrhart, are both biodynamic wine producers – at separate wineries – but he doesn't quite agree with her stance that omitting sulfur can make for an exciting and more terroir-driven experience. His argument: consistency and quality of the product are at risk. Hers: when it's done well, it's beautiful.

"Sans soufre (without sulfur) is a new philosophy for the family," says Zusslin. "I like pure aromas and I think my Crémant d'Alsace Brut Zéro is proof that you can have bright, pure wines without adding sulfites." She's quick to add that she'll only make her wine this way in ideal conditions. If there is any risk of the wine being unstable, she will add sulfur to it before bottling.

When it comes down to it, Dr. Waterhouse says the question of sulfites in wine is a philosophical one – at least for now. Until concrete evidence of sulfites' side effects can be reached, a preference for wines made without them is more about the idea of making a purer wine without an extra additive.

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