What You Need to Know About Sulfites in Wine

Sulfites are a universal ingredient in wine that confers many benefits related to maintaining and maximizing the quality of wine. However, over the years many concerns have risen about sulfites in wine. 

What Are Sulfites?

Sulfites are sulfur compounds, also called sulfur dioxide, or SO2. They naturally occur in wine as a result of the fermentation process, and additional sulfites may also be added. 

Sulfites vs. Sulfates

Sulfites and sulfates are both sulfur compounds. Sulfites are used as preservatives in food and wine, and are also used in some medications. Sulfates are used in magnesium supplements and various household products, notably Epsom salts and detergents. Sulfates are widely used to produce a lathering effect in soaps. 

Why Are Sulfites Added to Wine?

Sulfur is added to fresh grapes to protect the fruit from oxidation and added to wine during fermentation to preserve color, reduce microbial activity, and stabilize pH levels that could cause a wine to go wrong very quickly. It is added in higher doses to stop fermentation or prevent refermentation in sweet wines.

Are Sulfites Bad for You?

While sulfites are largely considered safe to consume, they can cause issues for people who have certain sensitivities and allergies. As such, if you suspect that you are negatively affected by sulfites, you should consider choosing lower-sulfite wines. 

Sulfite Allergies and Intolerance

Anyone can have a sulfite allergy or intolerance, but people with asthma may be particularly susceptible, with approximately 4 to 5% of people with asthma having some form of sensitivity to sulfites. Possible symptoms and side effects of sulfite allergies and intolerance include:

• Wheezing;
• Shortness of breath;
• Coughing;
• Chest pain;
• Sinus congestion;
• Throat tightness;
• Belly pain;
• Nausea;
• Diarrhea;
• Vomiting;
• Cramps; 
• Skin rash;
• Itching;
• Hives; 
• Warmth;
• Redness; 
• Skin inflammation;
• Dizziness;
• Light-headedness;
• Paleness;
• Weak pulse;
• Fainting. 

If you experience any such symptoms, it is important to speak to your doctor. They may advise you to choose lower-sulfite options or to avoid foods and beverages containing sulfites altogether. 

How Much Sulfur Is in Wine?

The amount of sulfur in wine depends mainly on the type of wine being made. Because sulfur has a powerful smell and causes severe reactions in people who are allergic to it, there are legal limits as to how much sulfur can be added. These limits vary by country, but wine importers must adhere to the destination country’s policies.

Does Some Wine Have More Sulfur Than Others?

Some wine types need more sulfur than others to stay stable. For example, sweet wines need more sulfur than dry wines, so they do not start to re-ferment in the bottle. Sweet wines may have up to 250 mg per liter of SO2. White wines are second in line. Dry whites generally have up to 100 mg per liter of SO2, which helps to prevent them from turning brown. Red wines have a natural preservative (anthocyanin) in their skin and need less sulfur, usually about 75 mg per liter. 

The maximum SO2 allowed in any wine in the United States is 350 mg per liter.

Do all Wines Have Sulfites?

The short answer is yes. All wine has a little sulfur. This is because sulfur is a by-product of the fermentation process; therefore, all wine contains some naturally occurring sulfur. However, sulfur is also added to the wine. If you purchase a wine that says “no sulfur added,” it will still have some sulfites present.

Do Organic Wines Have Sulfur?

Most (but not all) organic wines are made with minimal sulfur added. However, just because a wine is organic, there’s no guarantee it doesn’t have some sulfur. An organic designation only applies to vineyard practices, not winemaking.

Wine With Low Sulfites

As mentioned, there are no wines that are completely sulfite-free (even if they are advertised as such). However, you may be able to find wine with relatively low sulfite content. Red wines are typically lower in sulfites than white wines. Wines that indicate “no added sulfites” on the label may also be a good option. It is important to bear in mind, however, that sulfites naturally occur during the fermentation process and therefore these wines simply do not have sulfites artificially added during the production process.

Can You Smell or Taste Sulfur in Wine?

The legal amount of sulfur in wine is well below the taste threshold. Excessive sulfur is usually corrected in the winery before bottling the wine for sale. But sometimes, when a wine is judiciously sulfured and is warmed slightly, you will notice a distinct sulfur or matchstick-like smell. This smell usually blows off quickly by decanting the wine or with a swirl of the glass.

If you are a wine enthusiast who is concerned about the health impacts of sulfites in wine, it may be in your best interest to stick to sampling wines that have low sulfites or at least no added sulfites. Thankfully, these are by no means rare, especially among red wines. It will be easy to accommodate your preferences whether you are attending a dinner party, visiting a winery, or receiving a wine subscription.