Why is it so difficult to make a (good) SO2-free wine?
Sulphur dioxide (SO2) in wine is a controversial and misunderstood beast. Some consider it poison, ready to attack with a headache, hangover or allergic reaction. Others believe that it strips away the inherent personality of a wine and its sense of place. While individual motivations may vary, there are plenty of wine producers attempting to reduce and eliminate the addition of SO2 from their wines, and natural winemakers are leading the charge.
Taste enough sulphite-free wine and you may find a certain lack of consistency. If you’ve ever wondered why that is – why it’s so difficult to make a good sulphite-free wine – you’re in the right place.
Why is it so hard to make good sulphite-free wine?
To answer the question, we’ve first got to establish why sulphites are added in the first place. Alcoholic fermentation can produce sulphites naturally, so why bother adding any more?
The primary reasons for adding sulphites to wine are as a preservative and disinfectant. SO2 helps to protect against oxidation, and its antimicrobial qualities assist against unwanted aromas. Producers can opt to add sulphites directly to freshly-harvested grapes or otherwise before fermentation, during fermentation or later in the winemaking process.
Remove sulphites from the equation, and the likelihood of oxidation, spoilage and the development of off-flavours and aromas can shoot way up. Making a good (or great) wine in sulphite-free conditions is not easy, though by no means impossible.
How do you make a good wine without adding SO2?
Making wine without SO2 additions runs many risks, but skilled winemakers can still yield excellent results.
Hygiene is hugely important, and a meticulous attention to cleanliness in the cellar and during winemaking is crucial to avoid contamination. The juice and wine must be handled and stored with utmost care at every step of the process. It is virtually impossible to make a good quality sulphite-free wine without keeping a spotless production area.
Some winemakers may even choose to pasteurise their sulphite-free wine. The process of pasteurisation uses heat to kill all micro-organic life within the wine, ensuring that the yeasts and bacteria within cannot spoil the wine. Pasteurisation is not a realistic option for natural winemakers and those interested in low or minimal intervention, and it can have a serious impact on the wine’s ageing potential.
More likely than sulphite-free production is the gradual and incremental reduction of sulphite additions. Many wine producers are today experimenting with techniques to bring down their reliance upon SO2, though for various reasons it is not preferable to simply eliminate their use at once. As technologies and techniques improve and become more widely adopted, chances are that the quality of sulphite-free wines will become a whole lot more consistent, too.