Science

Natural wine and sulphites: what the science actually says

2026-10-15 · Source: International Organisation of Vine and Wine (OIV)

Key figures

Legal max (EU, conventional) Red: 150 mg/L · White/Rosé: 200 mg/L · Sweet: 400 mg/L

Natural wine (self-regulated) Most producers: 0–30 mg/L total SO₂

Naturally occurring SO₂ Fermentation produces 10–40 mg/L without any addition

Allergy threshold (estimate) Reactions typically require >300 mg/L; rare below 100 mg/L

OIV position Sulphur dioxide is an oenological practice recognised as safe at permitted levels

What sulphites do

Sulphur dioxide (SO₂) has been used in winemaking since Roman times, when winemakers burned sulphur candles inside amphorae before filling them. It serves two distinct roles: as an antimicrobial agent, it prevents unwanted bacteria and wild yeast from spoiling the wine; as an antioxidant, it slows the oxidation that eventually makes wine flat and stale. Without sulphites, winemakers must rely on scrupulous cellar hygiene, inert-gas blanketing and rapid bottling to protect wine through its journey from fermentation vessel to consumer's glass.

The EU's permitted maximum levels vary by wine type: conventional dry reds may contain up to 150 mg/L total SO₂; dry whites and rosés up to 200 mg/L; sweet wines (where the residual sugar creates a greater microbial risk) up to 400 mg/L. In practice, well-made conventional wines contain considerably less than the legal maximum. The December 2026 EU nutrition labelling rules — see the EU nutrition labels article — will require sulphite content to be disclosed on-bottle or via QR code.

What the natural wine movement does instead

Natural wine producers — those working under charters like France's Vin Méthode Nature — typically add no sulphites at all, or add only a minimal quantity (5–30 mg/L) at bottling. The trade-off is vulnerability: natural wines require cool storage, careful transport and consumption within a shorter window than conventional wines. Some natural wines develop reductive notes (rubber, struck match) or oxidative character (nuts, dried fruit) that would be faults in conventional wine but are accepted as stylistic features in natural wine. The line between intentional character and genuine fault is a matter of significant disagreement among wine professionals.

For how sulphites interact with storage conditions and why oxidation matters, see the How to store wine guide and the How wine is made guide.

Sources: OIV (sulphur dioxide oenological practice standards); EU Regulation 2019/33 (permitted SO₂ levels); AWRI (SO₂ use in winemaking research); IFOAM Organics (organic winemaking standards); Demeter (biodynamic certification standards). Published: 2026-10-15. Corrections via the contact form.

Questions

About sulphites and natural wine.

Do sulphites cause wine headaches?

The evidence is weak. Sulphite-sensitive individuals exist — roughly 1% of the population, mostly asthmatics — but the "sulphite headache" narrative is not supported by controlled trials. Red wine contains less sulphur dioxide than many conventional white wines and far less than dried fruit, yet red wine is more associated with headaches. Other candidates include histamines, tyramines, tannins and simply the higher alcohol in red wine. The OIV notes that sulphites at permitted levels are generally well tolerated.

Is natural wine always sulphite-free?

No — fermentation produces 10–40 mg/L of sulphur dioxide naturally, regardless of any addition by the winemaker. A "no added sulphites" wine still contains some SO₂. True zero-sulphite wine is technically impossible unless the wine is processed to remove all free and bound SO₂ after fermentation. Many natural wine producers add a small amount (5–30 mg/L) at bottling for stability, which they disclose on the label. The EU requires "contains sulphites" on any wine above 10 mg/L total SO₂.

Why do winemakers add sulphites?

Sulphur dioxide serves two functions: as an antimicrobial agent (preventing unwanted bacteria and yeast from spoiling the wine) and as an antioxidant (slowing the oxidation that turns wine stale). Without sulphites or equivalent intervention, wine is more vulnerable to faults — particularly volatile acidity (vinegar notes) and premature oxidation. This is why no-sulphite wines require careful winemaking, ideal transport conditions and often shorter drinking windows. See the How long an open bottle lasts guide for how oxidation affects wine after opening.

Are natural wines better for you than conventional wines?

There is no scientific evidence that natural wines are healthier. The relevant risks of wine consumption relate to alcohol, not sulphite levels. From a health perspective, the alcohol content (ABV) is the most material factor regardless of how the wine was made. Anyone with a genuine sulphite sensitivity should check labels and look for low-sulphite wines, but most people have no need to seek them out on health grounds. For responsible drinking guidance, see the NHS alcohol advice pages.

How is natural wine defined legally?

There is no legal definition of "natural wine" in the EU or UK. The term is used voluntarily by producers and broadly covers minimal-intervention winemaking: native yeast fermentation, no fining or filtration, no or minimal sulphite addition. Several producer associations have developed their own charters — Vin Méthode Nature in France (certified, maximum 30 mg/L total SO₂) is the closest thing to a regulated category. The How wine is made guide explains conventional winemaking steps as a reference.