September 25, 2024 - 0 comments
Why Does My Natural Wine Say It ‘Contains Sulphites’?
The short answer is that grapes naturally produce sulphites, and so does yeast during alcoholic fermentation, so even without added sulphites, they are naturally present in wine.
But let’s look at the longer answer to the question:
Both industrial and indigenous yeasts found on grapes and used in spontaneous fermentation for natural wines— have residual levels of sulfur dioxide (SO₂), or sulphites. Yeasts, particularly those from the genus Saccharomyces, convert grape sugars into alcohol and carbon dioxide. They produce some sulphites to inhibit harmful bacteria and spoilage as part of their defense mechanism.
Although most sulphites in wine develop during the alcoholic fermentation process, small amounts may also be present on the grape skins before harvest. Vines naturally produce traces of sulfur compounds as part of their metabolism, mainly in response to environmental stress or pathogen attacks. Winemakers also often treat their vines with Sulfur to protect against problems like oidium.
After that, we have added sulphites. Conventional winemakers are allowed to add sulphites during many steps of the winemaking process (harvest, fermentation, aging, bottling, cleaning, etc.). As a result, conventional wines are allowed up to 150 mg/l for reds and 200 mg/l for whites).
This is not the case for natural winemakers, who aim not to use any additives at all. However, a very small amount of sulphites is tolerated and some natural winemakers might use it, if really needed, at bottling to protect wines from oxidation and spoilage. This is why we consider a wine as natural when total sulphites are below 30mg/l for reds and 40 mg/l for whites.
Since sulphites are classified as allergens, potentially causing reactions in sensitive individuals, EU regulations require that any wine with more than 10 mg per liter of SO₂ (added or occurring naturally) display 'contains sulphites' on the label.
That’s why even natural wines with no added sulfites must still display 'contains sulphites' if they exceed the legal threshold.
So, next time your friend asks you what that mention means, you can let them know. Cheers!
