Sulfites comprise a range of sulfur compounds—particularly sulfur dioxide (SO2)—that are a natural by-product of the fermentation process that work as a preservative against certain yeast and bacteria (which will quickly destroy a wine if they start to multiply). But fermentation alone doesn’t produce enough sulfite to preserve a wine for more than a few weeks or months in the bottle, so winemakers add extra in order to keep microbes at bay. Sulfites aren’t just in wine. Many, many foods ranging from crackers to coconut contain sulfites. Anything that’s at all processed is likely to contain at least some level of sulfites.
In 1986, the FDA identified sulfites as an allergen, following a rash of asthma cases reported around that time. Sulfites were promptly banned from raw fruits and vegetables, and as part of the warning label push in the late 1980s the feds required that sulfites be disclosed on wine labels if they could be detected at a level of 10 mg/L or higher. If you prove your wine has less than that, you can apply for an exemption—thus so-called “sulfite-free” wines exist. Though many foreign producers include US warning labels, technically the rules only apply to domestic wines. Either way, sulfites are a regular part of winemaking around the world as a matter of necessity. Just because your bottle of Chateauneuf-du-Pape doesn’t have the warning doesn’t mean it isn’t full of sulfites.
Can I Smell Sulfites in Wine?
Very sensitive tasters have been noted to smell sulfur compounds in wine, although sulfur compounds are somewhat unrelated to sulfites. Sulfur compounds in wine called thiols range in flavor from citrus-like smells to cooked egg-like smells.
What’s interesting is that the warmer the wine, the more molecular sulfur it releases. This is why some wines have a nasty cooked-egg aroma when you open them. You can fix this issue by decanting your wine and chilling for about 15-30 minutes.
The Headache Conundrum
Put simply, sulfites are to wine as gluten is to food. While the FDA says the overall prevalence of “sulfite sensitivity” is unknown, it notes that it is “probably low” and is most frequently associated with severe asthmatics.
Do sulfites cause headaches? Legions of drinkers say they do. Science says they don’t. A 2008 study in The Journal of Headache and Pain on alcohol and headaches said that even in individuals with asthmatic sulfite sensitivity, sulfites have not been shown to cause headaches. The study goes on to say that “On the other hand, there are many foods such as dried fruits, chips, raisins, soy sauce, pickles and juice fruits containing concentration of sulphites [sic] even ten times higher than that of wine.”
That said, many people do experience headaches when drinking red wine, so much so that Red Wine Headache has been acryonmmed to RWH. While the science is as yet unclear, major suspects include histamine and tyramine, two natural chemicals that can mess with blood pressure and lead to headaches. (Fun fact: Red wines have more histamine, but white wines usually have much more sulfite.) There’s also the inconvenient argument that wine contains lots alcohol, which has a significant dehydrating—and thus headache-inducing—effect.
But let’s say you have an asthmatic sulfite sensitivity but still want to drink wine and want to get rid of the sulfites. Or maybe you still think sulfites are giving you a headache. Is there a way they can be removed from wine after it’s already in the bottle?
It turns out there is, and that method is far less high-tech than you might think. The solution lies in a familiar brown bottle in every suburban bathroom: hydrogen peroxide. Hydrogen peroxide oxidizes sulfites, turning sulfite into hydrogen sulfate, which does not cause the types of problems that are associated with sulfites. It’s long been said that a few drops of H2O2 in your wine will eliminate the sulfites altogether, at least in theory. A number of products on the market also claim to eliminate sulfites in wine. 2SO2GO comes in a small bottle that is sprayed into a glass of wine. Just the Wine comes in a tiny bottle and is applied via drops in much the same way, directly into the glass.
To conclude, we think that the rare cases in which individuals suffer allergic reactions to sulfites notwithstanding, most vintners will certainly agree that eliminating sulfite additions is both unwise and unnecessary. There’s a tendency to polarize these issues, to make it black and white but things are often different; one has to be judicious regarding this decision. Let’s not throw out the baby with the bath water.
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