Is Sulphur Dioxide in Wine Safe to Drink?

January 11, 2026 •

4 min read

According to the U.S. Food and Drug Administration (FDA), less than 1% of the general population is sensitive to sulfites, the compounds formed by sulphur dioxide, with the majority of those affected also having asthma. Most people can safely consume wine containing sulphur dioxide without any adverse reactions.

Quick Summary

Sulphur dioxide is a common wine additive and natural byproduct of fermentation used for its preservative and antioxidant properties. While generally safe for most, a small percentage of people, particularly asthmatics, have a sulfite sensitivity. Regulatory bodies enforce strict limits on its use, and wine labels often indicate its presence when above certain levels.

Key Points

Sulphur dioxide is safe for most: The majority of the population can drink wine containing sulphur dioxide without any adverse health effects.
Acts as a preservative: Sulphur dioxide is a critical antioxidant and antimicrobial agent used to prevent spoilage and extend a wine's shelf life.
Small risk for sensitive individuals: A very small percentage of people, particularly asthmatics, can have a sulfite sensitivity, leading to allergy-like symptoms.
Not a cause of headaches for most: The common belief that sulphites cause wine headaches is a myth; research points to other compounds like histamines and tannins as more likely triggers.
Naturally produced and added: All wines contain some level of natural sulphites from fermentation, with winemakers often adding more for stability and preservation.
Levels are regulated: Food and beverage authorities in major markets regulate the maximum amount of total sulphites allowed in wine.

Sulphur dioxide ($SO_2$), a compound commonly used in winemaking, has often been a point of confusion and concern for consumers. Despite its somewhat alarming name, this chemical plays a vital role in protecting and preserving the quality of wine. The key takeaway for most people is that sulphur dioxide in wine is safe, and any negative health effects are typically limited to a very small segment of the population with specific sensitivities. Understanding its function, regulations, and natural occurrence can help demystify this common additive.

The Role of Sulphur Dioxide in Winemaking

Sulphur dioxide is valued by winemakers for its dual role as both an antioxidant and an antimicrobial agent. These properties are essential for producing a stable and consistent wine, especially for bottles intended for aging. Without $SO_2$, wine would be far more susceptible to spoilage from bacteria and unwanted yeasts, as well as rapid oxidation that would ruin its flavor and aroma.

Key Functions of Sulphur Dioxide:

Prevents Oxidation: Oxygen is a wine's enemy, causing it to lose its fresh fruit flavors and turn brown. $SO_2$ acts as an antioxidant, scavenging free oxygen and preventing oxidation that can lead to unpleasant sherry-like aromas.
Controls Microbial Growth: During fermentation, $SO_2$ is used to inhibit or kill off undesirable wild yeasts and bacteria that could produce off-flavors or spoil the wine. This allows the winemaker to ensure that the fermentation is carried out by a specific, cultured yeast strain.
Stabilizes and Preserves: By limiting microbial growth and oxidation, $SO_2$ extends the shelf life of wine. It ensures the wine stays fresh and stable, allowing it to be aged for years or stored and transported without risk of spoilage.
Enhances Color Extraction: In the production of red wine, $SO_2$ can be used to help extract color and tannins from the grape skins during maceration, contributing to the wine's final color and structure.

Natural vs. Added Sulphur Dioxide

It is a common misconception that sulphites are only present in wine due to human intervention. In fact, all wines contain sulphites because they are a natural byproduct of yeast metabolism during the fermentation process. This means that even 'no added sulphur' wines will have a small amount of naturally occurring sulphites.

Winemakers add additional $SO_2$ during various stages of production, such as crushing, fermentation, and bottling, to ensure consistency and prevent spoilage. The total level of sulphites in wine depends on several factors, including the type of wine (white wines typically have more than red), its pH, and sugar content. European Union regulations, for instance, set maximum limits of 150 mg/L for red wines and 200 mg/L for white and rosé wines.

Comparison: Conventional vs. Low-Sulphite Wines


Feature	Conventional Wine	Low-Sulphite/Natural Wine
Sulphur Dioxide Content	Higher levels, with additions made at several stages for stabilization.	Minimal or no added sulphur dioxide, though natural sulphites exist.
Preservation	Reliant on added $SO_2$ for long shelf-life and stability against oxidation and microbes.	Less stable and more vulnerable to spoilage; often requires quicker consumption.
Winemaking Process	More interventionist approach, controlling for consistency and shelf-life.	Emphasizes minimal intervention, focusing on vineyard health to reduce the need for additives.
Labeling	Labeled as 'Contains Sulphites' if exceeding 10 ppm, regardless of amount.	May also be labeled 'Contains Sulphites' if natural levels exceed 10 ppm.
Potential Health Effects	Adverse reactions possible for a small population with sulfite sensitivity.	Still contains natural sulfites, so sensitive individuals are not guaranteed a safe alternative.

Understanding Sulphite Sensitivity

While the name 'sulphur dioxide' sounds intimidating, its presence in wine is a minor health concern for the vast majority of people. The main health consideration is for those with a pre-existing sulfite sensitivity or allergy. It is crucial to distinguish between a general intolerance and a true allergy.

Sulfite sensitivity is a hypersensitivity reaction that does not involve the immune system and is not a true allergy. Symptoms often mimic allergic reactions and can include wheezing, hives, flushing, dizziness, and stomach upset. Individuals with asthma are at a higher risk of being sulfite-sensitive, with some studies estimating this affects between 5% and 10% of the asthmatic population. In rare cases, severe reactions like anaphylaxis have been reported, making it crucial for sensitive individuals to take precautions.

For the average person, consuming wine with normal levels of sulphites poses no significant health risk. In fact, many other foods, including dried fruit, processed meats, and condiments, contain significantly higher levels of sulphites than wine. Concerns about sulphites causing headaches are also largely unsubstantiated, with other factors like histamines, tannins, or the alcohol itself being more likely culprits.

Conclusion

Sulphur dioxide is an effective and widely used preservative that has been safely used in winemaking for centuries. For the overwhelming majority of consumers, it poses no health risks and allows for the stable production of high-quality, long-lasting wines. While it's important for individuals with confirmed sulfite sensitivity or asthma to monitor their intake and potentially choose low-sulphite options, the fear surrounding $SO_2$ in wine is often disproportionate to the actual risk for most people. As with any beverage, responsible consumption and being aware of personal sensitivities are the most important considerations.

For further reading on the science of winemaking and sulphur dioxide, you can visit The Australian Wine Research Institute (AWRI) which provides comprehensive technical details and research on the topic: Revisiting sulfur dioxide use - The Australian Wine Research Institute.

Frequently Asked Questions

Sulphur dioxide ($SO_2$) is a chemical compound used in winemaking as a preservative and antioxidant. It prevents wine from spoiling by inhibiting the growth of unwanted bacteria and yeasts and protecting it from oxidation.

No, but all wines naturally contain small amounts of sulphites as a byproduct of the fermentation process. Winemakers often add more to ensure consistency and stability, but the amount varies widely depending on the wine type and production methods.

Sulphur dioxide can cause allergy-like symptoms in a small percentage of the population with sulfite sensitivity, especially asthmatics. True sulfite allergies are very rare, but reactions can include wheezing, hives, and dizziness.

Wines labeled as 'no added sulphur' are available, but even these will contain small amounts of naturally produced sulphites from fermentation. True 'sulphite-free' wine is extremely rare and very unstable.

Generally, sweet white wines and off-dry whites contain more sulphites than dry red wines. Tannins in red wine and higher acidity levels in some wines provide natural protection against spoilage, reducing the need for high $SO_2$ levels.

While it's a common belief, sulphites are unlikely to be the cause of wine headaches for most people. Research suggests other compounds like histamines, tannins, or the alcohol itself are more probable culprits.

Yes, sulphites are widely used as a preservative in many processed foods, often at higher concentrations than in wine. Common examples include dried fruit, processed meats, condiments, and certain canned goods.