Sulfur dioxide preservatives, or sulfites, are one of the classes of chemicals widely used in winemaking. The reason you’ve probably heard about sulfites but no other chemical wine additive is that a small percentage of the population has sulfite sensitivities, and for those that do, drinking wine can cause rashes and other allergic reactions.
Wine naturally contains some sulfites, but winemakers must label that a product “contains sulfites” if the proportion exceeds 10 parts per million (ppm). Many other products contain sulfites — dried fruit can have up to 1,000 ppm. It’s more likely that your wine headache is related to other compounds in the wine — namely, tannins, histamines and, of course, alcohol.
Organic winemakers cannot add sulfur dioxide or other unnatural chemicals, so the best way to avoid sulfur dioxide is to opt for organic wines. Also, red wines contain fewer sulfites than white wines do because the tannins in red wine act as a natural preservative. White dessert wines generally have the most sulfites, followed closely by blush and semisweet wines.
Photo by iStockphoto/Liza McCorkle