Sulphur dioxide
Sulphites are a topic often debated among wine lovers. But what exactly are they? Sulphites are a group of chemical compounds containing sulphur. In wine, they are mainly present as sulphur dioxide (SO2). These compounds are naturally produced by yeasts and are added to wine for several reasons, including preventing oxidation, increasing its stability, inhibiting bacterial and fungal growth, and improving the quality and longevity of the product.
Are sulphites dangerous?
However, sulphites in wine are also a concern for many consumers. They can, in fact, cause allergic reactions in some individuals. Allergic reactions may include symptoms such as headaches, skin redness, breathing difficulties and even anaphylactic shock. The effects of sulphites in wine depend on various factors, such as individual sensitivity and the amount present in the wine. It is important to note that sulphites are present in many other foods besides wine, such as dried fruit and tinned foods. (Packaged lime and lemon juice: maximum permitted quantity 350 mg/l) Therefore, if you are allergic to sulphites or have adverse reactions to them, it may be necessary to limit your intake of all these foods. Government regulations and standards set the maximum amount of sulphites that may be present in wine.
What are the permitted quantities of sulphur dioxide in wine?
In the European Union, for example, red wines may contain up to 150 mg/litre of total sulphites, while white wines may contain up to 200 mg/litre. Organic wines generally contain a lower amount, as organic regulations limit the use of added sulphites. Natural wine allows concentrations below 30–40 mg/litre, while if the wording ‘sulphite-free’ appears on the label, the amount must be below 10 mg/litre.
Uses
Returning to the useful uses of sulphur dioxide SO2 in wine, it is worth stressing that the presence of this substance is important for preserving wine. Sulphites act as antimicrobial and antioxidant preservatives, helping to prevent wine oxidation and keeping microbes under control (so the wine does not turn into vinegar). This helps extend the wine’s shelf life and preserve its freshness and flavour. In addition, they can help stabilise the colour of the wine, preserving the pigments present in the grapes and controlling oxidation that could affect the shade and vibrancy of the colour.
Can they help?
Sulphites can help protect the flavour of wine by preventing the formation of unpleasant aromas and preserving its fresh, fruity bouquet. They are also used during the fermentation stage to control the growth of unwanted yeasts and promote stable fermentation. It is important to emphasise that the use of sulphites in wine is subject to regulations and limits established by food regulatory authorities, as some people may be sensitive or allergic to this substance.
Our wines
Our wines aim to be as sound as possible, which is why we seek to use sulphur dioxide properly and not excessively. The low content means that it is very important to store wine bottles correctly:
- Away from light
- good humidity
- no temperature fluctuations
Labelling rules
At European level, regulations require the wording “contains sulphites” to appear on the label when the concentration exceeds 10 mg/litre: a very low threshold, which explains why almost all wines on the market carry this warning, even when the content of added sulphites is minimal. This information requirement, designed to protect those with specific intolerances, should not be confused with a judgement on the quality of the wine.
Further reading
Further insights into wine quality and health: organic, biodynamic or natural wine, the effects of wine on health, wine ageing.
