Sulphur in wine – what is it for and how does it affect us?
It is believed that sulphur has been used in winemaking since 1487 and perhaps even earlier!
Sulphur dioxide (SO2) is a naturally occurring element and is used in winemaking to prevent oxidation and to inhibit unwanted yeasts and bacteria. It is present even in unsulphured wines due to the fact that SO2 is produced during fermentation.
If it is used at bottling in homeopathic quantities, then there is little or no effect on the wine or indeed the drinker. However, if used by the winemaker heavy-handedly, then it can make the wine smell like a struck match. It is believed that it can cause hangovers and allergic reactions.
During winemaking, the winemaker will often use SO2 at harvest time (a metabisulphite dusted over the grapes to inhibit the action of wild yeasts as well as oxidation). They may also use it during crushing and fermentation of the grapes, again to inhibit the effects of wild yeasts or to prevent malolactic fermentation. Finally, at bottling, it is often used to prevent oxidation and microbial spoilage.
In general, red wines need little or no sulphur (because of contact with antioxidants within the skins of the grapes during maceration and fermentation). White wines need more SO2 to prevent oxidation (as there is little or no skin contact) and sweet white wines require the highest doses.
SO2 can be detected at levels of around 11mg/l. At 20-30mg/l the smell can be unpleasant.
At levels of more than 10mg/l, the label must say ‘contains sulphites’.
In the EU the maximum permitted levels are as follows:
- 160mg/l red wine
- 210 mg/l white wine
- 400mg/l sweet wines
These do seem alarmingly high!
However, the World Health Organisation states that an average man should not consume more than 1/3rd of a bottle of white wine containing 200mg/l of SO2 for health reasons.
This is why most quality-conscious and caring winemakers are concerned about the use of SO2 in their wines. In reality, most self-respecting winemakers use levels of SO2 well within these limits.
All of our family of winemakers strive to make their wines with minimal sulphur dioxide. Indeed some winemakers like the Chevrots in Burgundy make some of their wines with no sulphur addition. In the same way, all of our winemakers without exception, prefer not to use herbicides and pesticides – which is why many are either organic or biodynamic. But that is a different story!
Montirius did some tests on their wines a few years ago and found that after a short period of time, the amount of sulphur within their wines could barely be detected.
Owner Christine Saurel said ‘even in our white wines and roses (our most ‘fragile wines’) we use less than 14mg/l of sulphur during ageing, but never at bottling. Within a year, this level turns to zero in bottle as it is absorbed naturally within the wine.
There will doubtless be more wines made with little or no sulphur in the future. However, the ability for some of these wines to age long term might be questionable. But in this modern era of living in the ‘here and now’ rather than the future, this is likely to become less of an issue for most.
Sulphites in wine tend to get the blame for all sorts of allergies and hangovers. However, there is one school of thought that suggests that only about 1% of wine drinkers are in fact sensitive to sulphites.
What is more likely to cause discomfort when drinking wine is the alcohol itself (!), the proteins used to fine the wine during winemaking (which can cause an allergic reaction), histamines and tannins (which can also cause an allergic reaction) and other compounds called Oligosaccharides.
Oligosaccharides are molecules found in the cell walls of grapes.
Much research work is currently taking place to determine what effect they have on the wine drinker. Watch this space…!