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Contains Sulphites - Friend or Foe?

Contains Sulphites - Friend or Foe?

Richard Esling - Wednesday, March 15, 2017
"Contains Sulphites" Friend or Foe?

Words to strike the fear if God into you or superfluous information? Well, neither actually. It is a legal requirement that wines that contain sulphites must show the fact on the label. Since all wines contain sulphites, all wines have this information on their labels. A legal requirement in the States since 1988 and in the EU since 2005. But what are they, why are they there and what do they do? And most important of all, are they bad for you?

Sulphites are a range of sulphur based compounds (most commonly sulphur dioxide or SO2) that occur naturally in low levels in wine. The higher levels in nearly all wines, are as a result of the addition of sulphites to the wine at varying stages in the wine making process, or just before bottling. The reason for their addition, is that they have excellent properties as a preservative, to keep the wine fresh and prevent oxidation, where the wine turns to acetic acid, or vinegar.

However, the science involved is not as straightforward as it may seem. When sulphur dioxide is added to the wine, some of it is immediately bound to other components present, and some of it remains 'free'. It is only the 'free' SO2 that has the desired anti-oxidant effect, the bound sulphur having no effect at all. Even more complicated, is the fact that over time, more and more of the free SO2 will become bound, thus reducing the preservative effect still further. Thus, the wine-maker will have to calculate just how much sulphite to add so that the wine is protected for its normal drinkable lifetime, which may vary from a year or two, to 30 years or more.

At least, that's what should happen, so that the amount of sulphur dioxide is kept to the absolute minimum necessary. In certain commercial, bulk wines, that appears not always to be the philosophy, and higher amounts are added 'just in case'. But is that a problem and are there unwanted, or even dangerous effects of sulphites in wine? It is a debate which goes on endlessly in the wine world, with no really definitive answer.

One quite clearly bad effect of sulphites is for the relatively small percentage of the population which suffers from asthma or other breathing problems. In those which are particularly sensitive to SO2, an allergic response can be triggered, and hence the warning on wine labels, a little like another labelling phrase “May contain Nuts”. But what of other oft talked about effects, such as headaches and even nausea? There appears to be no scientific evidence linking sulphites to headaches, but equally no evidence to discount the effect.

Headaches and other untoward effects of wine may well be due to a whole host of other, natural, constituents present, but good old sulphites often takes the blame. The levels in wine are actually far less than in some other foodstuffs where sulphites are used as a preservative, such as dried apricots or commercial orange squash. Will Lyons, wine columnist for the Wall Street Journal, suggested in an article, that a test to see if you are sensitive to sulphites, is to eat some dried apricots and observe the effect. They can contain ten times the amount found in wine.

The effect of SO2 on the wine itself, however, is also under debate, many wine-makers believing that it can mask or subdue flavours in the wine. Hence the resurgence of ‘natural’ wines, with no added sulphites. That the level of added sulphites should be kept to the minimum is un-disputed, but whether or not they cause headaches or other health problems other than to asthmatics, is much more contentious. What would be helpful, is that the level of sulphites be indicated on the label and a scale produced for comparisons. 

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