What is the big deal about sulphur and wine?
The ancient Roman and Greek civilisations were quick to discover sulphur’s qualities as a preservative. Sulphur was used to seal cracks in their amphorae but when it was used for internal repairs, they soon discovered it was soluble (not so helpful!) and was, more importantly, stopping their precious wine from deteriorating into vinegar. There are documents from the first century AD that describe sulphur being burnt inside wine vessels to prevent oxidation. When we talk about oxidation in the negative sense it’s when the wine, exposed to air for too long, begins to turn brown and take on vinegary aromas.
If we skip on a few millennia to the twentieth century the presence of sulphur in wine production is widespread. It is being used to kill off the unwanted bacteria and yeasts and to prevent premature oxidation. Wine producers have realised that grape skins, split and torn in rough harvesting can be temporarily ‘band-aided’ with a sprinkling of SO2. Barrels and wineries are regularly cleaned with it and frequently, come bottling, a dash more sulphur is added for stability and enduring freshness. At this point in time you might well have come across a wine that contained 500 mg/litre of sulphur.
Is sulphur all bad and is there such a thing as "sulphur-free wine"?
It is important to say at this stage that the demonisation of sulphur isn’t fair. For a start it’s a natural by-product of the fermentation process. There is no such thing as a 100% sulphur-free wine. Also, homeopaths use the sulphur mineral to treat some skin problems. It is not necessarily dangerous. Equally the role of sulphur in ‘cleaning up’ the winemaking act has been important. It has played a crucial part in helping winemakers deliver consistent, stable wines to a very happy wine-drinking community. Nonetheless, widespread use of sulphur products in convenience foods, canned foods and dried fruit has seen a rise in sensitivity to sulphur and so it’s important we know how to reduce our exposure to it if we can. As an aside, there is typically more SO2 in one dried apricot than in a glass of wine.
A few numbers and rules about low-sulphite wine
An unlucky wine drinker in the 1960s might have hit on a bottle that had 500 mg/litre of sulphur in it but by the 1990s the EU had stepped in and restricted permitted levels to half that. Today the legal limit they’ve set is 150 mg/litre for red wines and 200 mg/litre for white wines. Better still, organic wine drinkers are exposed to less sulphur because their limits are 100mg/litre for reds and 150mg/litre for white. Some sweet wines are permitted to have up to 400mg/litre, though the average tends towards 220mg/litre. This is because sulphur combines with the sugar first before the remaining ‘free’ sulphur can do its job.
If the total SO2 in a bottle of wine exceeds 10 (yes ten) mg/litre, then EU law dictates that “contains sulphites” must appear on the bottle.
Working towards minimising sulphites in wine
For some winemakers these reductions and limits don’t go far enough and are aiming for lower-levels still or, more ambitiously, to add no sulphur at all. For other winemakers, the move to less sulphur is about maximising the wine’s individuality and authenticity. As beneficially cleansing as sulphur can be, it undoubtedly mutes a wine’s personality when used to excess.
What to expect from low-sulphur / no-sulphur-added wines
So, how do you look after your low-sulphite wines? Well, not much differently than normal! They’re best kept in a cool spot and away from natural daylight. White wines can be kept for up to two years and reds for up to five, depending on the wine style. You can, if you choose, decant the red wines – no fancy gear required, just pour into a jug and then back into the bottle.
One of the characteristics of no-sulphur-added (aka NSA) wines is that they will oxygenate more quickly than other wines and so it’s quite possible that the wine will change from one glass to the next, which is great fun.
Any bad news? Well yes; there are those that will tell you sulphur in wine is the cause of many wine headache. We don’t doubt you – sulphur sensitivity is a real thing. So too is alcohol and if you drink too much of it, NSA or not, a headache may well follow!
Drinking no-added-sulphur wines is a rewarding choice. You will be drinking a carefully crafted wine that is the result of attentive vineyard management and eagle-eyed vinification. Often hugely expressive, NSA wines give a less-interfered expression of the place the vines are grown and of the individual grape varieties and chances are, you will taste the wine’s story unfold further, glass by glass.