Clipped to a board on the wall of a small Loire cellar, the addition log for a single cuvée of Chenin Blanc runs eleven lines down a sheet of A4. Three are sulfur additions, all in milligrams per litre: 20 mg/L at pressing, 10 mg/L after malolactic, and a pencilled “10 mg/L if total falls below 25” ten days before bottling. The number that matters is not any single dose. It is the cumulative ceiling the arithmetic implies: this wine, if all three additions land, will leave the cellar around 25 to 30 milligrams of total sulfur dioxide per litre. That ceiling is not the winemaker’s invention. It is a regulatory number, and France was the first government to write it down.
The natural-wine argument over sulfur has run for the better part of two decades on instinct and tribe. One camp insists that any added SO2 disqualifies a wine from the category; the other counters that some sulfur is the difference between an honest cuvée and a faulty one. Until 2020, neither camp had a regulator-adjacent number to anchor the line. France’s Vin Méthode Nature framework, launched that year, is the first official designation to settle the argument with a real threshold.
What France actually wrote down in 2020
The Syndicat de Défense des Vins Naturels (SDVN) launched Vin Méthode Nature in 2020 with the support of France’s Institut National de l’Origine et de la Qualité (INAO), the Ministry of Agriculture, and the DGCCRF (the consumer-fraud directorate). The syndicate, per Wine Spectator, defends the designation against infringement, audits growers, and awards accreditation. The framework is not state-issued certification in the sense of an AOC, but it is regulator-adjacent: it lives inside the French agricultural-quality infrastructure, and the launch carried Ministry endorsement.
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The core of the framework is a ceiling, not a recipe. Per Wine Spectator: “Growers are allowed to add a small amount of sulfur dioxide (SO2) prior to bottling, as long as the final wine contains less than 30 milligrams per liter.” Thirty milligrams per litre is the line, and the framework splits the certified universe into two tiers around it. Vin méthode nature sans sulfites ajoutés is the zero-addition logo. Vin méthode nature avec moins de 30 mg/l is the second logo, awarded to wines that received post-fermentation additions but still tested below 30 mg/L total at bottling.
The two-tier structure matters because it acknowledges what working winemakers already know: a small pre-bottling addition can stabilise a fragile wine without changing what it is. Forbidding any addition is a different methodological commitment from capping the total at a level so low it falls inside the threshold where SO2 has measurable sensory effect. The framework rewards both decisions and asks producers to disclose which one they made.
How 30 milligrams compares to the legal maximum
The number lands differently once it sits next to the ceilings written into ordinary wine law. Per the Napa Valley Wine Academy, the United States caps wines at a federal maximum of 350 parts per million total sulfites. That is the legal upper bound for any wine sold in the American market; most commercial wine sits well below it. But the federal maximum is the frame inside which the natural-wine argument has been running, and 30 mg/L sits at roughly one-twelfth of it.
The American disclosure floor sits on the other side of the arithmetic. Per the Napa Valley Wine Academy: “Since 1987, the U.S. has required any wine with 10 ppm or more of total sulfites to clearly display the phrase Contains Sulfites on its label.” A Vin Méthode Nature second-tier wine at 25 to 30 mg/L is therefore roughly three times the American disclosure floor and one-twelfth of the federal ceiling. The French number is not zero. It is a calibrated middle, written into the rule rather than implied by the practice.
The 10 ppm trigger produces the small-print “Contains Sulfites” line on the back of virtually every American bottle, including those produced naturally. One reason the natural-wine argument has been hard to ground in the American context: the disclosure line is so universal it has become invisible, and the federal ceiling so high it is irrelevant to the cohort the argument is about. France’s 30 mg/L sits between the two thresholds and inside neither.
The politics are louder than the chemistry
The chemistry of SO2 in wine is settled. Sulfur dioxide binds aldehydes, suppresses spoilage organisms, and protects the wine from oxidation. The settled chemistry has not settled the argument, because the argument has never been primarily about chemistry. It has been about what a producer is willing to declare, and about whether the trade should reward zero-addition cellar work with a category of its own.
At root it is a labour and disclosure argument. Working without sulfur additions requires cleaner fruit, faster cellar work, lower yields and more vigilant temperature control during fermentation, and the producer must accept that some vintages will not yield wines stable enough to ship without intervention. Producers who do the work and ship the wines have argued, for two decades, that the trade owes them a way to say so on the bottle. Producers who do most of the work but reserve the right to a small pre-bottling addition have argued, with equal force, that the category should not be defined to exclude them.
Vin Méthode Nature is a compromise structured as a hierarchy. It validates the zero-addition position by giving it its own logo, and admits the small-addition position into the same framework by giving it a second, capped at 30 mg/L. The framework’s authority comes from the regulators who endorsed it and from the syndicate that audits it. The 30 mg/L line is not chemistry; it is the number the French agricultural-quality apparatus and the natural-wine syndicate could both sign.
Reading the label, late 2025
On a French wine shelf or list in late 2025, the framework’s two logos have begun to appear in places they did not five years ago. The zero-addition sans sulfites ajoutés logo sits on back labels of producers in the Loire, Beaujolais, Auvergne, Jura and Languedoc whose work was previously verifiable only through trust, importer reputation, or trade gossip. The avec moins de 30 mg/l logo sits on a wider cohort who have always worked at very low total SO2 and now have a way to say so in print.
The American shelf does not yet have a counterpart. The TTB’s 10 ppm disclosure floor catches nearly every bottle, and the 350 ppm federal ceiling is functionally invisible. American natural-wine producers who do the same cellar work as their French peers communicate it through importer copy, sommelier word-of-mouth, and back-label notes that are not standardised. A drinker who wants the equivalent of a second-tier Vin Méthode Nature cuvée in California or Oregon is reading shelf-talkers and trade lists, not labels.
The addition log on the Loire cellar wall reads the same as it did before 2020: three sulfur lines, two doses at 10 mg/L, one at 20 mg/L, a cumulative ceiling around 25 to 30 milligrams per litre at bottling. What changed is what the log is the working document for. Five years ago it was a private cellar record, legible only to the winemaker and an occasional importer who asked the right question. Now it is the evidence behind a logo on the bottle, the regulator-adjacent number that settled, for the first time, what the argument was actually about.
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