Sulphur, so good? What it really means when wine 'contains sulphites'

If you’ve ever found yourself in the unfortunate situation where a lack of sparkling conversation has left you reading the back of a wine bottle in search of entertainment, you’ve probably come across the words “contains sulphites”.

A mundane, descriptive phrase, that tells us a little about what we are drinking, but is surrounded by a debate that tells us a lot about the culture of modern wine drinking.

The debate around sulfur dioxide in wine is made up of, mainly well intended, half truths, hotly held opinions, often tedious technicalities, and some very thoughtful insights and approaches to the craft of making great wine.

Sulfur dioxide (SO2) is used in winemaking for its antioxidant and antimicrobial properties. It stabilizes and preserves wine, preventing spoilage from unwanted bacteria or excessive oxidation during the winemaking process and the wine’s life in bottle.

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The benefits of adding sulfur dioxide to wine are pretty straightforward, and for the vast majority of winemakers globally, preserving and protecting wine with small doses of SO2 is simply convention.

So what are the downsides? From a consumer perspective, the most obvious is the potential effect of added sulphites on a drinker’s health. As someone who sells wine for a living, I often hear people’s concerns that they are allergic to sulfur dioxide in wine, with symptoms ranging from wheezing and tight chestedness, to debilitating headaches. Allergies to sulphites definitely exist, but the numbers are relatively small. As always, if you’re concerned, speak to your doctor.

SO2 can be highly toxic, but only in large concentrations. The legal upper limits of sulfur dioxide in wine sit between 200-400 parts per million, depending on the sweetness and color of the wine – the tannins in red wine are antioxidants, meaning lower additions are necessary.

Most producers use less than half of that. In reality, the quantities of sulphites added to conventionally made wine are far less than those found in many processed foods, from fruit juice to tomato sauce, mayonnaise or tinned fish. Some dried fruits have more than 20 times the amount of sulphites added as you’ll find in a bottle of wine.

Are added sulphites bad for your health? It seems unlikely.

To be fair, most of the conversation about sulphites in wine centers not on what they do to us, but what they do to our wine. And that conversation is largely inseparable from the natural wine movement.

Broadly, the idea of ​​natural wine is that grapes should be allowed to ferment and become wine without the input of external additives, nutrients and preservatives designed to manipulate that process. Sulphites, especially when added during fermentation, arrest or alter that process.

Winemakers who have experimented successfully with making wine without any sulphites added report their wines have brighter flavours, more complexity and more energy, and that by comparison their sulphured wines are somehow muted. During the last couple of decades conventional winemakers have generally started to wind back the amount of sulphites they add to wines for similar reasons.

I had the interesting experience of tasting a number of different white wines with a winemaker I greatly respect, each of which he presented in a version with zero sulphites added, and another with a very minimal amount of sulphur.

My impression at the time was that there were easily identifiable differences between the wines, and the zero sulfur wines were more immediately open, broader and perhaps more complex, while the others were more precise and focused.

At the time my preference was for the low sulfur wines, but realistically on a different day my preferences may have been the opposite. A bit like choosing between Daniel Carter of the 2005 Lions tour, and Daniel Carter of the 2015 world cup. Both divinely good, but in subtly different ways.

Decisions about adding or not adding sulphites are complex and technical, best understood by experienced and thoughtful craftspeople. Their motivation is, for the large part, to explore ways of making wine differently that lead them towards making something they feel is better to drink.

Where the debate about sulphites in wine goes sideways is when the absence of SO2 is held as a virtue in itself, that somehow that omission has automatically made the wine better, regardless of how the wine actually tastes.

There are elements of posturing and puritanism around the question of sulphites in wine, along with a tendency to categorize wines in a way that misses a lot of the nuances between wines and winemakers, and does little to help us find better wines to drink.

Three wines without added sulphites to try: