I was helping out on the sales floor at a Binny's last Wednesday when I was asked a familiar question - Do you have any sulfite-free wines? This was already on my mind for the upcoming and ongoing series of blog posts on green wine, so I was eager to jump into my spiel:

  I pulled the customers over to the section of organic and sulfite-free wine. I pointed out that they were all certified organic, and that some are labeled no added sulfites while others were labeled no sulfites detected and that sulfites are naturally occurring in tiny quantities in all wine, and that we carry lots of other certified organic and organically grown in other parts of the store, and that some of them are biodynamic ... and that's where they cut me off.

  We just need wine without sulfites. It's a gift for a friend who has a sulfite allergy.

  Oh, I said. These are what you're looking for.

  This is exactly the reason that the most wines bear the label contains sulfites. Just like peanuts in candy bars and phenylalanine in chewing gum, a small percentage of people have extreme allergic reactions to sulfites, while the rest of us shouldn't worry much about their use. But that warning contains sulfites sounds all chemically and kind of scary, which may help breed misconceptions on the subject.



  Sulfites act as a preservative in wine -  preventing oxidization (as an antioxidant), keeping the color bright and the fruit fresh, as well as sterilizing the environment and inhibiting secondary fermentation that might occur in bottle from wild yeasts and residual sugar.

  In modern winemaking, the term sulfites most commonly refers to sulfur dioxide (SO2), a colorless gas. It is often created by adding potassium metabisulfite (or sometimes sodium metabisulfite) to the must the mixture of grapes and juice early in the winemaking process, and SO2 is released. The wine is made in an SO2-rich environment, and some of the molecules bind with other chemicals in the wine. Potassium metabisulfite looks like a grainy white powder.

  In early winemaking you know, Greek and Roman times sulfur was used as a sterilizer in wine barrels. It would be burnt and would combine with oxygen in the air to create a SO2-rich environment. But this would smell like sulfur, like a burning match. So we've gotten away from that.



  The most common misconception about sulfites is that they cause headaches. They do not.

  Many people do experience headaches after drinking red wine. This is sometimes caused by overindulgence, but it is likely that other compounds present in wine cause reactions in certain people. If you suspect that sulfites cause your headache, remember that white wine often contains the same amount, if not more, than red wine. Also, sulfites aren't just used in wine they are commonly used as a preservative in dried fruits, and in much higher concentrations (legally as much as 5x) than in wine. My guess is that not many people suffer from dry fruit headache.

  Some people, like the friend of those customers I helped a few days ago, really are affected by sulfites. If you have a sensitivity, chances are that you already know about it. To help protect this group a fraction of a percent of people all wines sold in the U.S. have carried a required warning label since 1988.

  So what's the difference between no sulfites added and no sulfites detected? Wines which are USDA certified organic contain less than 10 parts per million of naturally occurring sulfites (organic certification is a subject for another blog entry). These qualify as no sulfites added. Sometimes, no sulfites are detected, and the label can claim such, but sulfites probably do occur in undetectable amounts.

  Remember, I'm not a doctor, I'm a wine bloggist. If you have serious concerns about your sensitivity to sulfites, talk to your doctor. For the rest of us, the bottom line is this: Don't freak out about sulfites.


  For a quick overview of sulfites in wine, check out Karen MacNeil's The Wine Bible, and for more information, see Jancis Robinson's Oxford Companion to Wine. Both are available at select Binny's locations, and also on my bookshelf.