Sulfites in Wine

Sulfites are byproducts of sulfur dioxide used since the days of the Romans and Egyptians for cleansing wine containers. Sulfites were approved for use in the United States in the early 1800s to preserve foods. The antioxidant and antimicrobial properties of sulfites have made them invaluable to winemaking. The sulfites are routinely added during the winemaking process to either inhibit or kill bacteria and wild yeast allowing rapid and clean fermentation of wine grapes. Also, sulfites are a natural and minor byproduct of yeast fermentation and are produced during the wine fermentation process. Levels in wine average 80 mg/liter. The only wines made without added sulfites are wines labeled as "Organic Wine." To bear the USDA organic seal, the wine must be made from organically grown grapes and may have naturally occurring sulfites, but the total sulfite level must be less than 20 parts per million. Wines that are labeled "Made with organic grapes" can contain added sulfites. This is an important distinction. Wines labeled "Made with organic ingredients" or "Some organic ingredients" may or may not have added sulfites.

Although sulfites are perfectly safe for most people, there are selected individuals with asthma and others who are deficient in the natural enzyme to break sulfites down who are particularly sensitive. Reportedly, 8 percent of the world's population is allergic to wine. About 1% of people are sulfite-sensitive, but in asthmatics, the figure is closer to 5%. Steroid-dependent asthmatics are at most risk for a severe reaction. Even among the asthmatic population, however, a relatively high sulfite level exposure is required for a reaction. Since 1985, the FDA has required foods such as wine to indicate on the label the presence of sulfites to alert the small percentage of people to the possible problems associated with consuming sulfite-containing food. Wines with more than 10mg/liter must have a “Contains Sulfites” warning label and only wines with less than 1mg/liter can state “No Sulfites” on the label.

The symptoms of sulfite sensitivity are usually mild and consist of a skin rash accompanied by redness, hives, itching, flushing, tingling and swelling. In more sever cases, respiratory symptoms can include wheezing, difficulty breathing, and loss of consciousness.

The headaches, stuffy noses, and rosy cheeks that some people develop after drinking red wine are not related to the sulfite content of the wine but probably due to other substances contained in wine such as histamines, tyramine and tannins. These symptoms do not progress to a more serious reaction. Tannins have been shown experimentally to stimulate blood platelets to release serotonin and increased serotonin levels can be associated with headaches. Alcohol itself may be a factor for it is known to precipitate migraine headaches in genetically predisposed individuals. Choosing wines naturally low in tannins, such as white wines, as well as red wines that are lower in tannins like Pinot Noir may reduce the risk of headaches. Drinking wine with food is also helpful. To test out a wine, try a half glass and wait 15 or 20 minutes. If the wine is going to cause a headache, it will likely do so within this time. If there is no reaction, the wine drinker should be fine as long as they imbibe in moderation. Ingesting aspirin, ibuprofen or acetaminophen before drinking may block the “red wine headache syndrome,” but consult your doctor before taking these medications on a regular basis.

A 2010 study published in the Journal of Proteome Research discovered that there are 28 glycoproteins in a Chardonnay that are similar to allergens found in other foods. These proteins are derived from the grape itself and created during the fermentation process. A definite casual relationship between glycoproteins and wine allergy have not been established. The hope is that someday the winemaker may be able to remove unwanted allergens without altering the flavor of the wine, creating a low or non-allergenic wine.