Contain sulphites: Why does this appear on wine labels and should I be concerned?

Master of wine and scientist Caroline Gilby puts sulphites under the microscope to explain what they are and why you're likely to find them in your glass.

A lady reading a wine label on a bottle

Sulphites in wine

Alcohol is a strange category under EU law, because alcoholic drinks over 1.2% alcohol are currently exempted from mandatory listing of ingredients and making nutrient declarations, something that's obligatory for most food products. However, since 2005 it has been a legal requirement to declare sulphites on the label if the level is over 10 mg/l (even if of natural origin - a small amount is always produced during fermentation). Very nearly all wines have some sulphur dioxide, or its sulphite compounds, added during winemaking or before bottling because this is the most effective means of protecting wine from oxidation and microbial instability. Under EU law, limits are strictly controlled to 150 mg/l for dry red wines and 200 mg/l in dry whites and rosés, with higher levels for sweet wines. It's worth noting that this is considerably lower than the levels permitted in dried fruit such as apricots (2000 mg per kilogram are permitted), while other products containing notable sulphite levels include prepared salads, burger meat and even frozen chips.

The potential problem with sulphur

The EU recognises that sulphur dioxide and sulphites are a problem for up to 1% of the population, who may react badly, and it continues to conduct research into what is an acceptable level of sulphites to protect both consumers and producers. Already organic wines have 50mg/l lower limits than conventional ones, and across the board, responsible producers tend to be careful about using just enough sulphur dioxide to protect their wines but no more. A couple of other surprising things may sometimes appear on wine labels. Since 2012 it's been obligatory to declare residues of egg or milk if measured at levels above 0.25 mg/l – again about protecting consumers with allergies. Egg and milk products are permitted as processing aids to clarify wine – in case you wondered why they are there at all.

Changing times for wine labelling

Information on wine labels
In the next couple of years, wine labels may well change significantly, and have to provide a lot more information

In the next couple of years, wine labels may well change significantly, and have to provide a lot more information. The EU has decided that alcohol can't justify being exempt from full labelling and has given the wine industry a chance to come up with voluntary proposals for providing nutritional information and ingredient labelling. The initial report published in 2018 suggests that typical energy content based on a standardised serving will go on the label (dry wine comes in at 324 KJ or 77 kcal per 100ml – though note that a typical pub wine serving is 175ml), with other information provided via a weblink or QR code. There is still debate about how to classify in oenological substances into processing aids and additives/ingredients. This matters because the industry is proposing that processing aids and natural substances used to adjust grape composition won't be declared at all (this would include acids, sugar and concentrated grape must). Processing aids used properly shouldn't be present in the final wine - however their use is still a matter of concern to strict vegans as many processing aids are derived from animal products. It's not clear whether the European Commission will accept the wine industry's proposals at all, or whether it will impose ingredient labelling on the wine industry. Either way watch this space - within the next few years, consumers will have a lot more information about what goes into a glass of wine beyond grapes.

Caroline Gilby MW

Guest Writer

Caroline Gilby MW

Caroline Gilby is a Master of Wine and a scientist by training. She is a wine writer with a passion for the wines of Central and Eastern Europe and contributes to several wine books, magazines and websites.

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