September 2011 Edition

Sulphur – The good, the bad and the not-always ugly

Sulphur dioxide (SO2) is the most widely used and controversial additive in winemaking. Its main functions are to inhibit or kill unwanted yeasts and bacteria and to protect wine from oxidation.

Unfortunately for many people, they suffer intolerances and allergic reactions to the sulphurs, especially where there are slightly higher concentrates than one should be ingesting. Reactions range from severe headaches, blocked noses and itchy eyes to rashes and hives and in very extreme cases, could even result in death. Are you allergic to sulpha in medication? Work it out… Sulpha = Sulphur…
SO2 is added at several points in the process of conventional vinification and is present in the finished wine in the form of sulphites, which occur naturally in all living things and are present in small quantities even in unsulphured wines.

Sulphur dioxide should not be confused with the powdered sulphur which is sometimes dusted onto vines to protect them from powdery mildew (called oidium in French), even in organic viticulture.

It is often claimed that the Romans used sulphur to preserve their wines, but the evidence for this is vague. The first explicit mention of its use in winemaking is a German royal decree in 1487. This permitted winemakers to burn sulphured woodchips in barrels used for storing wine.

This is an effective method of disinfection and is still a common practice (using pure powdered sulphur rather than woodchips) although steam-cleaning is now an alternative.

The systematic use of sulphur dioxide to control fermentation and to stabilise the wine at bottling was perfected by the French in North Africa early in the twentieth century. It was a way of making wine in conditions that were essentially too hot. This approach quickly caught on in other climates, as a way of making wine without having to worry about it.

Most winemakers will tell you that it is not possible to make good wine without sulphur dioxide. This is not true, however the risks are such that very few winemakers are prepared to take them.

Rash caused by sulphur intolerance

A rule of thumb is that red wine doesn't need additional sulphur as it gets enough anti-oxidants from the skin contact it gets, whereas white wine and many rosé's don't have the skin contact, which means that sulphur is often added to these wines. It is however the sweeter wines that are the main culprits in the saga as they require the sulphites more particularly to overcome the high levels of sugar. Think sherry, late harvests, straw wine or ice wine.

We must also recognise that in certain circumstances sulphur dioxide is the only option. Used at bottling (in homeopathic doses) it does little or no damage to the flavour of the wine and can help to protect it from being mishandled.

There are four points at which sulphur dioxide is commonly used in conventional winemaking, although the winemaker may choose to make further additions if he is feeling nervous.

• Picking - Applied in the form of metabisulfite to inhibit the action of wild yeasts and prevent oxidation. It means the grapes don't have to be rushed to the winery.

• Crushing - To prevent fermentation from beginning with wild yeasts before cultured yeasts can be added. Cultured yeasts are bred to be more resistant to SO2.

• Fermentation - At any point during fermentation, but most commonly at the end to stop or prevent malolactic fermentation. A natural winemaker has to wait for the "malo" to finish naturally.

• Bottling - To prevent oxidation (or any other microbial action) in the bottled wine. In sweet wines there is the danger that fermentation will restart.

A natural winemaker would only ever use sulphur dioxide at bottling, only in white wines, and only in very small quantities. Many natural winemakers use none at all.

If you find a wine that you particularly enjoy, you can take a look at one of the following two options that will help break down the sulphites:

• Decant it into a Captain's decanter (one of the very wide ones) for an hour before drinking and slosh the wine about a fair bit. Apparently contact with the air helps change the sulphites to sulphates. For whatever reason it seems to help.

• Don't have too much. The difference is that an intolerance is broadly linear, whereas an allergic reaction has some kind of trigger level. Watch out how long it takes for symptoms to appear, so a first day can cause no issue, but puts the base level up. A similar exposure the second day can then cause a problem.

Ultimately, if you're a real wine lover and don't want to give up your favourite tipple any time soon, then take the time to search for wines that are labeled to be low in sulphites or organic wines.

Examples of South African producers who take their low-or-no-sulphur wines seriously are: Packwood , Avondale and Stellar Winery.

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