"True Facts" Sulfites in wine: Friend or Foe?

Sulfites refer to the family of sulfur-based compounds, some of which occur naturally, and others that are made commercially. Those most commonly used in winemaking are a gas, sulphur dioxide (SO2), and a powder, available as potassium metabisulphite. It seems hard to justify the use of something that sounds so very chemical and unnatural in my wine, yet sulfites are naturally produced by many organisms and found in such food items as grapes, oranges, cabbage, garlic and the onion family, and chicken eggs. They are even produced by our own bodies at close to a gram per day. Because of the antioxidant and antimicrobial properties of sulfites, they are used as preservatives for dried fruit, canned goods, shrimp, fruit juice, potato chips, and just a huge list of common food products.

Potassium metabisulfite is a common wine or must additive, in which it forms sulfur dioxide gas (SO2). This both prevents most wild microorganisms from growing, and it acts as a potent antioxident, protecting both the color and delicate flavors of wine. It is purchased as a white powder or salt containing approximately 57 percent sulfur dioxide. Potassium metabisulfite also comes in tablet form, known as Camden tablets.

• The use of sulfites in winemaking is a natural process that's been used by winemakers for a couple of thousand years, with the benign purpose of keeping your wine from spoiling before you can drink it. Ancient literature through the ages is loaded with techniques and handwringing over methods to preserve foods, grape juice and wine. Ancient wine preservation methods

• In modern winemaking sulfites in the form of SO2 may be used to clean winemaking equipment like barrels to insure that spoilage bacteria like brettanomyces do not become established in the winery. Sulfur compounds are added directly to the uncrushed grapes as they come in from the field, or immediately after crushing to tame wild yeast strains and other bacteria so that winemaking yeasts can take charge of fermentation.

• Then during fermentation, some winemakers will add sulphur to protect the must from contact with oxygen. Because it will kill the yeasts, it may be added later to actually halt fermentation if some residual sugar is desired in the finished wine, such as with German Rieslings or dessert wines.

• A final and perhaps most critical dose of SO2 is added to protect the wines while they are being shipped around the world. Even more importantly for wines that are to be cellared, the final sulfite additions are there to prevent oxidation, assuring that the finest wines will last and mature for decades or more. At each winemaking stage it is the stabilizing and antimicrobial effects of sulfur dioxide (SO2) that are desired, as well as its ability to bind with oxygen (which “oxidizes”, ages or hastens to spoilage) and certain aldehydes responsible off aromas and flavors.

You are probably NOT sulfite sensitive...

• The FDA estimates that 1% of the population is sensitive to sulfites. This works out to 4-5% of asthmatics in particular, who are so sulfite-sensitive that they must avoid sausages, pickles, canned tomatoes, dried fruits, condiments and many other good things - in addition to wine - in order to avoid an asthmatic reaction (tingling, redness, itching and a swollen tongue, and then depending on severity, progress to hives or an asthma attack). See Wine and Asthma (page 4), Wine Allergy?  and  Wine and Headaches

• If you get a headache or a stuffy nose after drinking wine, you may be allergic to something - possibly the histamines in some red wines, or in the case of hangovers, low tolerance to alcohol or simple over-indulgence! More (much) information on histamines in wine You might be experiencing something called Red Wine Headache Syndrome (RWHS), but it's not the sulfites.

• Actual sulfite levels in wine range from about 10 to 150 parts per million (ppm).  The legal maximum for wine in the United States is 350ppm. White dessert wines (sweet) have the most sulfur, followed by medium-sweet white wines and blush wines because these types of wine need the most protection due to the risk of re-fermentation of the residual sugars. Dry white wines generally have less, and dry reds have the least. Often not recognized is that red wines contain far less sulfur than white wines. This is partly because the tannins in red wines act as a preservative, making sulfur dioxide less necessary.

 

• Due to the real sensitivities of some (very few) the FDA begin requiring a prominent "Contains Sulfites" warning on every bottle of wine made or imported into the United States after 1986 with SO2 greater than 10ppm. Consider that about 10 - 20ppm occurs naturally in wine so the FDA rule covers just about every wine on my shelf and in your cellar. Despite the fact that virtually every winemaker in the world uses sulfites, the sudden appearance of the warning on United States wine labels has led to the mistaken belief that U.S. wines have "extra chemicals." Oddly, the fact that raisins, soy sauce, pickles, fruit juices and many other foods can contain as much as ten times more sulfites than wine doesn’t really seem to register.

Some wine producers, including many “organic” wine producers label and sell wines with no added sulfites. The key word is "added": Wine with zero sulfites is an unlikely thing, because they are a natural product of fermentation; the sulfites naturally created when the wine is made. Wines with less than 10ppm sulfites can be labeled as “sulfite free”, and these are very rare indeed, but are a blessing to those wine lovers who really are sulfite sensitive.