Sulphites in wine: What are they and why are they used?
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by Alastair C
2 min reading time
What are sulphites, and where do they come from?
From a chemistry perspective, sulphites are chemical compounds containing the sulphite ion, commonly found in the form of sulphur dioxide (SO2). While used as a preservative in various foods and beverages, it's important to know that sulphites in wine are naturally occurring. The fermentation process naturally creates sulphur dioxide as a by-product, meaning all wine contains sulphites.
Why are sulphites used in wine?
Preservation: Sulphites are vital in preserving wine against yeast and bacteria, without which wine can quickly turn into vinegar. They help balance the winemaking process by giving yeast a helping hand against bacteria that can cause wine to smell like vinegar or acetone.
Preventing oxidation: Sulphites act as antioxidants, preventing wine from oxidising.
Maintaining freshness: They help maintain the wine's freshness and taste.
Sulphites in other foods and labelling
While wine gets attention for containing sulphites, many processed foods also contain at least some sulphites. Examples include baked goods, processed meats, jam, tinned vegetables, frozen potatoes.
Labels that read "Contains Sulphites" might be a bit deceiving. A more accurate descriptor would be "Contains at least 10 mg/L of sulphites," reflecting the labelling requirement in most of the world for declaration of sulphites as an allergen.
Sulphites in wine and food in the UK
Sulphites are widely used in the UK, with maximum permitted levels of 150 ppm for red wine (100 for organic), 200 ppm for white and rosé wine (150 for organic).
Dried fruits like apricots and raisins usually contain sulphites, ranging from 500 to 3,000 ppm. Other typical foods containing sulphites in the UK range from 10 to 200 ppm, with regulations ensuring safe consumption.
Sulphite allergies and the "Wine Flu Myth"
While identified as an allergen, most people are not allergic to sulphites; only about 1% of the population has a severe sulphite sensitivity. Many attribute headaches after drinking wine to sulphites, but studies have not linked sulphites to headaches, even in people with asthmatic sulphite allergies. The assumption that sulphites cause headaches appears to be a correlation, not causation, as complaints occur even with "sulphite-free" wines. Indeed, if sulphites were to blame, you would expect more complaints about white wines and rosé, whilst the reverse is true. It turns out the more likely cause for those with a genuine sensitivity reaction might well be histamines, but that’s the subject of another article. For the rest of us, drink more water and keep hydrated!
Conclusion
Sulphites play a vital role in wine and many processed foods. From maintaining the vibrancy of dried apricots to balancing the winemaking process, their diverse roles are significant. While concerns and myths exist about sulphites, regulations and research provide insights that ensure their levels are within safe limits for consumption.
If you have specific concerns, do seek specialised professional medical advice, this article is for general information purposes only.
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by Alastair C
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