What Are Sulfites and Why Are They in Wine?
Sulfites are chemical compounds containing the sulfite ion (SO$_{3}^{2-}$), and they have been used as a preservative in winemaking for centuries. They function primarily as antioxidants and antimicrobial agents, preventing wine from oxidizing and spoiling. Sulfites are found in two forms: naturally occurring ones produced by yeast during fermentation and added ones introduced by winemakers. This is why no wine is truly sulfite-free, even those labeled as such, as they still contain naturally occurring sulfites. The quantity of sulfites in wine varies widely, and federal regulations require a label warning if the level exceeds 10 parts per million (ppm).
The Truth About Sulfite Sensitivity
Contrary to popular belief, sulfites are generally not the cause of the common 'wine headache'. The Food and Drug Administration (FDA) estimates that only about 1% of the population has a genuine sulfite sensitivity, with a higher prevalence among individuals with asthma. For most people, headaches associated with wine are more likely caused by other factors, including: tannins, histamines, dehydration, and the alcohol content itself. For the small group of people with a true sensitivity, symptoms can include respiratory issues, skin reactions, and digestive discomfort, which are often more severe than a simple headache. If you have been diagnosed with a sulfite allergy, or have asthma, it is important to consult a healthcare provider for personalized advice.
Methods to Reduce Sulfites (Not Eliminate)
While complete elimination is not possible, several methods can be used to reduce sulfite levels in an opened bottle of wine.
Aeration and Decanting
Aerating wine involves exposing it to air, which allows volatile compounds, including a portion of the free sulfur dioxide (SO2), to evaporate. Decanting a wine by pouring it into another vessel is a classic method that serves this purpose, though swirling the wine in a glass can also help. This process is most effective for removing the 'free' or unbound sulfites, which are more volatile than the 'bound' sulfites, but it does not eliminate all sulfites.
Sulfite Removal Products
Several products are available on the market, such as drops and wands, that claim to reduce sulfites. Many of these products utilize small, controlled amounts of hydrogen peroxide (H2O2) to oxidize the sulfites. While theoretically effective, the results can be inconsistent because the initial sulfite content of the wine is unknown. Over-application of these products can also negatively affect the wine's taste, potentially imparting oxidized or metallic notes.
Filters and Purifiers
Companies like Üllo and PureWine produce special filters and wands designed to selectively remove sulfites. These products often use a food-grade polymer or other resins to absorb sulfites and histamines. The effectiveness of these products is debated, but many users report a reduction in negative side effects. The Üllo device, for example, is placed over a glass or decanter and the wine is poured through it.
Comparison of Sulfite Reduction Methods
| Method | Effectiveness | Speed | Flavor Impact | Cost |
|---|---|---|---|---|
| Aeration/Decanting | Partial reduction of volatile sulfites. | Slow (30+ minutes). | Minor, can improve taste by opening up aromas. | Low (just a decanter or glass). |
| Sulfite Drops/Wands | Can reduce sulfites, but with inconsistent results. | Fast (minutes). | High potential for altering flavor if overused. | Moderate. |
| Specialized Filters | Claims selective removal of sulfites and histamines. | Fast (pours instantly). | Minimal, designed to preserve natural flavor. | High (initial purchase and replacement filters). |
Choosing Low-Sulfite and No-Added-Sulfite Wines
For those with sensitivities, seeking out wines with lower sulfite levels is the most straightforward solution. Wines labeled 'Organic' in the U.S. contain minimal or no added sulfites and must contain less than 10 ppm of naturally occurring sulfites. 'Natural' wines are made with minimal intervention and often use little to no added sulfites. Additionally, red wines generally require fewer added sulfites than white wines because the tannins from grape skins act as natural antioxidants.
Cooking with Wine and Sulfites
If you are using wine for cooking, the heating process can cause some of the free sulfites to dissipate. However, it's important to note that cooking does not completely eliminate sulfites, and for those with severe sensitivity, relying on cooking alone may not be sufficient. For best results, use a low-sulfite wine in your recipes or consider a non-alcoholic alternative.
Conclusion: The Bottom Line on Sulfites
Ultimately, you can't get rid of sulfites in wine completely, but you can effectively reduce them using several different methods. For the majority of people, sulfites in moderation are harmless. However, for the small percentage with a true sulfite sensitivity, reducing or avoiding them is an important health consideration. By understanding the different methods—from simple aeration to specialized filters—and knowing which types of wine are naturally lower in sulfites, you can make informed choices that work for your body without sacrificing your enjoyment of wine. For more in-depth information on the chemistry of wine, the University of California, Davis, is a leading authority on the subject.
