Are sulfates and sulfites in wine the same thing?
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Dear Dr. Vinny,
Are sulfates and sulfites the same thing?
—Vaibhav, Dindori, India
Dear Vaibhav,
Both sulfates and sulfites are sulfur-based compounds, but they are not the same thing. Sulfates are salts of sulfuric acid, and you probably encounter them daily, but not in wine. Sodium lauryl sulfate is a common type of detergent that removes grease by binding oil to water, and it’s in dish soap and other detergents—some people feel it’s too harsh to be used directly on your skin or hair, which is why some shampoos and other products are advertised as "sulfate-free." Epsom salts are also made of sulfates.
Sulfites are naturally occurring compounds found in wines; they help preserve wine by inhibiting microbial growth. Consuming sulfites is generally harmless, and they are found in a few other things, from molasses to dried fruit. But some people—particularly asthmatics—are allergic to sulfites, which is why you see the warning on wine labels that wine contains sulfites. Unfortunately, that label also creates confusion because people that experience headaches or flushing after drinking wine often wrongly blame sulfites for these issues.
Even though sulfites are naturally occurring, most winemakers also decide to add sulfur dioxide during the winemaking process to ensure against spoilage.
—Dr. Vinny
