Almost every bottle of wine on the planet contains sulphites. The label declaration "contains sulphites" has been mandatory in Europe since 2005 and in the United States since 1988, yet most wine drinkers have only a vague idea of what these compounds actually are and why they are so widespread. This article answers those questions directly, and says where we stand.
What sulphites are
Sulphites are sulphur-containing compounds that include sulphur dioxide (SO2) and its salts: sodium sulphite, potassium metabisulphite, and others. In wine they exist in two forms: free and bound. The free form is the biologically active one, capable of performing a protective function. The bound form is linked to acetaldehyde, sugars, and other compounds and is essentially inactive. What appears on the label is total sulphites — the sum of both.
A small quantity of SO2 is produced naturally during alcoholic fermentation by yeast: even a wine made with no added sulphites at all will generally contain between 10 and 30 mg/l. This is why "no added sulphites" is a different claim from "sulphite-free": the first is a technical, verifiable statement; the second is practically impossible to guarantee.
Why sulphites are used
Sulphur dioxide performs two main functions in wine:
- Antimicrobial. It inhibits unwanted bacteria and yeasts, both in the cellar during vinification and in the bottle after bottling. It reduces the risk of refermentation and bacterial spoilage.
- Antioxidant. It binds to oxygen before the oxygen can react with the wine's compounds, preventing oxidation of aromas and colour. It is particularly important for white wines and rosés, which are more sensitive to oxidation than reds.
For these reasons the use of SO2 has been established for centuries — the Romans burned sulphur inside amphorae — and it remains the most cost-effective winemaking additive in terms of results.
Legal limits in Europe
EU Regulation 2019/934 sets maximum total sulphite levels in mg/l. The values vary according to the colour, type, and residual sugar content of the wine:
| Wine type | Conventional limit | Certified organic limit |
|---|---|---|
| Dry red wine | 150 mg/l | 100 mg/l |
| Dry white / rosé wine | 200 mg/l | 150 mg/l |
| Off-dry white / rosé | 250 mg/l | 200 mg/l |
| Sweet wine (residual > 45 g/l) | 300–400 mg/l | 270–370 mg/l |
ICEA-certified organic wines — such as those of Tenuta Magrini — must comply with the lower limits in the right-hand column. For wines classified as "natural" under the codes of reference associations (VinNatur, AVN, Triple A), the thresholds fall further still: generally below 50–70 mg/l for dry reds and below 90 mg/l for whites.
Health considerations
Sulphites can trigger reactions in asthmatic individuals (an estimated 5–10% of asthmatics are sensitive) and, to a lesser extent, in people with specific hypersensitivity. The most common symptoms are respiratory; skin reactions are rare. The threshold at which effects appear in sensitive asthmatics is generally around 10 mg/l of free SO2 — well below any legal limit.
The headaches commonly attributed to sulphites are not confirmed in scientific literature as a direct effect of this molecule: biogenic amines (histamine, tyramine), oxidised tannins, and alcohol itself are more likely candidates. Nevertheless the widespread perception of the problem is worth taking seriously as consumer information.
Tenuta Magrini's approach
Our position on sulphites is pragmatic: we do not rule out the use of SO2 on principle, but we aim to use as little as possible and only when it genuinely serves a purpose.
In the vineyard we work under ICEA-certified organic farming, in force since 2023. In the cellar we work with healthy grapes, spontaneous fermentation with indigenous yeasts, and careful management of hygiene and oxygen exposure. This reduces the need for chemical intervention. Where the vintage allows — healthy grapes, clean fermentation, the naturally high acidity typical of Barbera — we add no sulphites at all, or a minimal dose at bottling: totals stay below 30 mg/l on Millecolli and Giglio Rosa, marginally above on Madonna dei Monti.
Each vintage is assessed individually. There is no declared "zero sulphites" policy set in advance, because we believe a minimal addition at the right moment is preferable to a flawed or compromised wine. Levels remain well within organic limits and, where possible, within natural wine association thresholds.
To see how this fits into our broader approach to natural winemaking, read our guide to natural wine. For an understanding of how cellar vinification affects sulphite decisions, see the article on spontaneous fermentation.