Discovering sulfites in wine: what are they, and what are they used for?

Sulfur dioxide is one of the most common additives used in the oenological field. This is a very commonly misunderstood topic; however, thanks to this guide, you will be able to discover the critical antiseptic, antioxidant, and preservative actions that sulfites exert, essential for the health, stability and quality of the wine.

What are sulfites in wine?

When we speak about wine, the term "sulfites” refers solely to sulfur dioxide, which is traditionally added to wine both in the form of salt (potassium metabisulphite) and liquid form. The disinfectant action of sulfites preserves the wine due to its disinfectant, antioxidant, and stabilizing properties.

The vast majority of the population enjoys wine with a meal, on a special occasion, or as a daily treat. It is often said that reactions to wine are caused by sulfites; however, the truth is a little more complicated. Sulfites occur naturally in some foods and drinks. For centuries, people have used them as food preservatives; for instance, nowadays, they are used to prevent shrimp and lobster from turning dark, reduce bacterial growth in wine, and preserve the flavour and freshness of wines. This is what you will need to know about sulfites in Frescobaldi wines.

What are sulfites used for in wine?

Wine is fermented using yeast, whose primary role is to convert sugars into alcohol and CO2; considering they are by-products of fermentation, all wines contain sulfites. Nevertheless, they have several positive effects on the winemaking process: including protection from oxidation, which can affect the colour and taste of the wine. 

There are two types of sulfites: natural and added.

1. Natural sulfites are just that, totally natural compounds produced during fermentation. This cannot be avoided; there are no completely sulfite-free wines. Sulfites are also a preservative, but the fermentation process alone does not produce all the sulfites needed to create the best Italian wines. For this, sulfur dioxide is added. Otherwise, many would find drinking a wine aged 50 years quite difficult.

2. Added sulfites, on the other hand, preserve the freshness and protect the wine from oxidation and unwanted bacteria and yeasts. Therefore, sulfites are among the most valuable compounds in circulation; they also positively affect the taste and aromas of the wine.

Are sulfites in wine bad for your health?

At the doses commonly used in the food industry, the majority of the population does not react to the presence of sulfites in food and beverages. However, two groups of people can be prone to side effects. Those suffering from sulfite-sensitive asthma can develop severe respiratory episodes after taking a high amount of sulfites. Similarly, people who lack the enzyme that breaks down sulfites could have severe reactions. Further research has yet to be done on what percentage of the population may be sensitive to sulfites. However, a person suffering from one of these conditions could have a reaction within 15 minutes of ingesting a large amount of sulfites.

Myths about sulfites in wine

People who suffer from headaches, perhaps after drinking wine, often blame sulfites; however, it is by no means clear that these compounds are really to blame. A headache can come after consuming a high amount of any variety of alcohol, while migraine sufferers can develop headaches with just a glass of wine. A common claim, for example, is that red wine causes headaches; however, in reality, white wine contains more sulfites than red wine; therefore, it is unlikely that sulfites in wine cause headaches. In addition, some foods like nuts and soy sauce contain a high amount of sulfites; if the sulfites in wine cause headaches, it seems logical that these foods should also cause a similar reaction.

Some experts suggest that drinking low-quality wine can cause headaches. However, these wines often contain compounds that can interfere with the production of serotonin, an essential chemical in the brain. Either way, headache triggers are likely to differ from person to person.

Sulfites in wine: what the law says

Considering that sulfites are naturally present in all wines, the European Union has not rejected their use. Instead, to avoid unpleasant events, especially in people with allergies and sensitivities to sulfites, the European Union has set limits on the amount of sulfites allowed to be present in wine. This means that today there are authorized maximum limits of sulfites (naturally present sulfites and added sulfites). The European Union has decided to impose a law that obliges winemakers to put an inscription on the bottle label, however, only on wines that contain more than 10 mg / l of sulfites.

On the other hand, there is also the label "without sulfites" this does not mean that the wine has zero sulfites; it solely refers to the fact that, during the vinification process, no additional sulfites were added artificially. It also signifies that the amount of sulfites in the wine is due to a natural production during fermentation, which does not exceed the limit set by the European Union. In order to get a better idea of the role of sulfites in wine and their organoleptic qualities, explore the ways wines are identified and classified in the designation of origins of wines.