2019 has been declared by UNESCO as the Year of the Periodic Table. To celebrate, we are releasing a series of blogs about our favourite elements and their importance to the chemical industry. Today’s blog is about sulphur, specifically sulphites and their significance to the wine industry.

 

Sulphites and wine - what is all the fuss about? Image: Pixabay

What is a sulphite?

Sulphites are compounds that contain the sulphite ion (sulphate (IV) or SO32- ). There a wide-range of compounds of this type, but common ones include sodium sulphite, potassium bisulphite and sulphur dioxide.

Sulphites are often added as preservatives to a variety of products, and help maintain shelf-life, freshness and taste of the food or drink. They can be found in wines, dried fruits, cold meats and other processed food. Some are produced naturally during wine-making however, they are mainly added in the fermentation process, protecting the wine from bacteria and oxidation.

Sneezing and wine

Sulphites have a bad reputation for causing adverse reactions, such as sneezing and other allergic symptoms. But are sulphites really allergens, or just another urban myth?

Despite it being one of the top nine listed food allergens, many experts believe that the reaction to sulphites in wine can be considered not a ‘true allergy’, rather a sensitivity. Symptoms only usually occur in wine-drinkers with underlying medical issues, such as respiratory problems and asthma, and do not include headaches.

 

Some people report sneezing and similar symptoms when drinking wine.

Sulphites are considered to be generally safe to eat, unless you test positive in a skin allergy test –some individuals, particularly those who are hyperallergic or aspirin-allergic, may have a true allergy to sulphites. Sufferers of a true allergy would not suffer very mild symptoms if they consumed sulphites, instead they would have to avoid all food with traces of sulphite.

Some scientists believe adverse reactions to red wine could be caused by increased levels of histamine. Fermented products, such as wine and aged cheese, have histamine present, and red wine has significantly more histamine than white wine. They suggest taking an anti-histamine around one hour before drinking to help reduce symptoms.

Sulphite-free wine!

Despite it not being considered a true allergen, wine-makers must still label wine as containing sulphites. In 1987, a law was passed in the US requiring labels to be placed on wine containing a large amount of added sulphites. Similarly, in 2005, a European law was brought in to regulate European wine labelling. Sulphites are now often listed as a common allergen on bottle labels in wines that have over 10mg/l.

 

You can often find the words ‘contains sulphites’ on a wine bottle. Image: Pixabay

Many food and drink industries are producing products suitable for allergy sufferers, and winemakers have followed this trend by beginning to make sulphite-free wine. These are mainly dry red wines that contain high levels of tannins, which act as a natural preservative. Wines without added sulphites are generally labelled as organic or natural wines and have grown in popularity over the last few years, but unfortunately, many wine critics believe that these naturally preserved wines sacrifice on flavour and shelf life.

In summary, sulphites are a common preservative, not only found in wine, but a range of food, and do not generally cause allergic reactions. If you are an individual with a true sulphite allergy, you may want to try sulphite free wine – but you will have to compromise on shelf life!