Few winemaking ingredients generate as much discussion as sulphur. You may see contains sulphites on a Bourgogne label, hear producers talk about using very little SO₂, or encounter wines marketed as having no added sulphur at all. Sulphur has been used in winemaking for centuries because it performs two particularly useful functions: it helps protect wine against oxidation and unwanted microorganisms. For a winemaker, the question is therefore rarely simply whether to use sulphur. It is when to use it, and how much.
What are sulphites?
When wine lovers talk about sulphur, they usually mean sulphur dioxide (SO₂) and the various sulphite forms associated with it in wine. Sulphites are not exclusively something added by the winemaker. Small quantities can occur naturally as a result of fermentation. This is why a wine made without added sulphur is not necessarily completely sulphite-free. The familiar contains sulphites statement on a label is therefore not evidence of heavy-handed winemaking. Under European rules, wines containing sulphites above the relevant threshold must declare their presence.
Why is sulphur added?
Wine is biologically and chemically active. Once grapes have been harvested and fermentation begins, the wine is exposed to oxygen, yeasts and bacteria. Sulphur dioxide helps the winemaker manage these risks. Its antioxidant role helps protect aromas, fruit and colour from unwanted oxidation. Its antimicrobial role helps control organisms that could cause spoilage or unwanted refermentation. This becomes particularly important during élevage and bottling, when a wine may need to remain stable for many years. For a bottle of Bourgogne intended for long ageing, that protection can be valuable.
When is sulphur used?
There is no single recipe. A producer might use a small amount when the grapes arrive at the winery, after fermentation, during élevage or shortly before bottling. Another may avoid additions during the early stages and make a carefully calculated addition only later. Some winemakers deliberately allow the wine to develop with very little sulphur before providing protection for bottling. The amount required also depends on the wine itself. pH is particularly important, because it influences how effectively sulphur dioxide works. The same numerical amount of SO₂ does not therefore provide identical protection in every wine.
Less sulphur, better wine?
Not necessarily. Modern quality-conscious producers often try to minimise unnecessary additions, but the lowest possible sulphur level is not automatically the best. Too much SO₂ can interfere with a wine’s aromatic expression and, at sufficiently high levels, become noticeable. Too little protection can create entirely different problems, including premature oxidation or microbial spoilage. The objective is balance. A carefully made Bourgogne may contain sulphur while still being produced with an extremely restrained approach to intervention.
What about no-added-sulphur wines?
Some producers make wines with no added sulphur, often described in French as sans soufre ajouté. This is possible, but it requires considerable care in both the vineyard and cellar. Healthy grapes, rigorous hygiene, controlled exposure to oxygen and careful handling become particularly important when the protective effect of added SO₂ is absent. Such wines can be expressive and fascinating, but avoiding sulphur does not itself guarantee quality. Nor does it mean the wine contains absolutely zero sulphites, since fermentation can naturally produce small amounts.
Sulphur and headaches
Sulphites are frequently blamed for the headache some people experience after drinking wine, but the connection is often misunderstood. A small proportion of people are genuinely sensitive to sulphites, with reactions particularly relevant for some people with asthma. This is the reason their presence is treated seriously as an allergen declaration. For most wine drinkers, however, sulphites are not considered the principal explanation for ordinary wine headaches. Alcohol itself, dehydration and other components of wine may play a role. It is also worth remembering that sulphites occur in many other foods and drinks.
Red versus white wine
The amount of sulphur needed can vary according to wine style. Red wines contain tannins and other phenolic compounds that provide some natural protection against oxidation. White wines generally have less of this protection and can therefore require a different approach. European regulations reflect these differences by setting different maximum sulphite levels for different categories of wine, with stricter limits applying to certified organic wines. These are maximum permitted levels, not targets. A producer may use considerably less.
Protection, not a quality mark
Sulphur is best understood as a winemaking tool. Just as with filtration, bâtonnage or the use of oak, its value depends on how and why it is used. A great winemaker does not necessarily avoid sulphur altogether, nor does adding sulphur indicate industrial winemaking. In Bourgogne, where wines may spend years or decades developing in bottle, a carefully judged amount can help preserve exactly what the producer has worked to create. The important question is not whether a wine contains sulphur, but whether the winemaker has used it intelligently and with restraint.