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If you've ever noticed a label that says “contains sulphite” when opening a bottle of wine, and that’s caught your attention, in this article, you'll find everything you need to know about the topic. Learn more about what sulphites are in wine, what they do and the levels of sulphites in organic wines.  

Los sulfitos del vino


Sulphites are a variant of sulphur oxides, primarily sulphur dioxide (SO₂), which are naturally produced during the fermentation process of the yeasts in the wine. SO₂ is used in a lot of the food products that we consume to stop them from losing their nutritional properties and conserve them over time.   

All wines contain naturally-produced sulphites. However, most of them are added during the wine-making process. We should mention that there are guidelines in the main wine-producing countries that limit the use of sulphites to low levels.  

We want to start this article by telling you that there’s no need to worry: very low levels, such as those used in the wine-making process are harmless.  


We're going to give you a quick run-down of the most common wines on the market so that you can know how many added sulphites they contain. Even though we mentioned that all wines contain sulphites, they don’t all contain the same amount. Let's take a look! 

  • RED WINE: these wines contain a lower amount of added sulphites. Red wines contain around 150 mg/l.  
  • WHITE WINES: dry whites contain a moderate dose, while semi-sweet and sweet white wines have the largest amount. These kinds of wines contain around 200 mg/l. 

In turn, wine that have low acidity levels need a greater amount of sulphites to ensure that they are conserved correctly since their structure is less stable. Wines with high sugar levels (off-dry wines, sweet wines, fortified wines, late-harvest wines) tend to need more sulphites than other wines. The added sulphites prevent a second fermentation of the residual sugars in the bottle.  

Wines with lower level of added sulphites are the ones that have a high alcohol content. These additives are necessary for sterilisation, but they only need a very low dose.  


Cantidad de sulfitos en el vino
Para qué sirven los sulfitos del vino


Adding sulphites to wine is a practice that dates back to many years ago. In the mediaeval period, many spices and honey were added to wine to mask the vinegary flavour that occurred over time. What’s more, wine-makers in Ancient Rome used to burn candle wicks made with sulphur in amphorae that contained wine.  

By burning the wick (thus creating sulphur dioxide), they stopped the wine turning into vinegar. This is what we mentioned at the beginning, sulphur dioxide (SO₂) helps to conserve the product; otherwise, the wine would turn into vinegar. SO₂ additives in the fermentation process helps to get rid of certain bacteria and yeasts, ensuring that there is a microbiological balance.  

  • Preservative: sulphites protect wine against oxidation when it comes into contact with air.  
  • Antiseptic and Antifungal Agent: sulphites can stop certain kinds of fungus from growing. They are used to disinfect the barrels by killing off bacteria and moulds. 
  • Stabiliser and Controller: they boost the best yeast and block the other ones. 
  • Solvent and Fining Agent: they accelerate the decomposition process in the fruit, boosting the release of tannins and aromas. 

Added sulphites can also stop the wine from losing its aromas, helping the product to develop better over time. So, now you know what sulphite are and the role they play in the wine-making process. But we're not done yet! We want to tell you what happens with sulphites in organic wines. Keep reading! 


Without sulphites, it would be almost impossible to conserve wine. Organic wines do contain added sulphites. Only wines that state that they are “No sulfites added” or “sulfite-free" on their label contain just the naturally occurring ones. These wines are known as natural wines. In this case, the legal limit is 100-120 mg/l. 

Have you heard about the launch of our new El Coto Crianza Organic 2019? This wine is made out of grapes from ecological agriculture, using eco-friendly wine-making methods and avoiding synthetic chemical products. Learn more about how we make this wine by following this link! 

If you found this article on sulphites in wine interesting, we recommend reading this article that discusses why wines get pricked. 

Why wines get pricked