Why Is Most Wine Dry?

Grape juice holds two main sugars, glucose and fructose, in about equal amounts. Yeast, mostly Saccharomyces cerevisiae, ferments them into ethanol and carbon dioxide. The UC Davis fermentation guide puts the aim plainly: convert all of the available sugar and leave no residual sugar in the wine.

Yeast eats glucose faster than fructose, so by the end of fermentation most of the sugar left is fructose. When the yeast finishes, a wine usually keeps under about 2 g/L, fructose plus small amounts of sugars yeast cannot ferment.

Each 1% of alcohol takes roughly 16.5 to 17 grams of sugar per liter, according to the Australian Wine Research Institute. A juice with 230 g/L of sugar ferments to about 13.5% alcohol.

• Chilling: cold stops the yeast before the sugar runs out. The grape’s own sugar stays in the wine.
• Adding spirit: Port producers add grape spirit partway through fermentation. The alcohol stops the yeast, and Port rules require more than 17.5 g/L of grape sugar left in the wine. Pedro Ximénez sherry is made the same way.
• Mixing juice and spirit before fermentation: a cartagène is grape juice blended with grape spirit, so the grape’s sugar stays in the wine.
• Very sweet juice: the more sugar a juice holds, the more it slows the yeast. One study of Riesling ice wine juice found that above 52.5 degrees Brix the juice would be unfermentable.
• Yeast limits: fermentation slows once the alcohol passes about 11 to 12% for many commercial yeasts, and earlier for some wild ones.

Acidity balances sugar. EU law builds this in: a still wine can be labeled dry with up to 9 g/L of sugar, as long as its acidity is no more than 2 g/L below the sugar. The rule reflects how acidity offsets sweetness.

A dry wine can smell and taste of ripe fruit without containing sugar. Alcohol at normal levels does not change how sweet a dry wine tastes, according to a 2018 Bordeaux study.

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These are the EU terms (Regulation 2019/33, Annex III, Part B). They are optional on still wine, and the sugar in the bottle may differ from the label by 1 g/L.

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On sparkling wine the sugar term is required, and the bottle may differ from the label by 3 g/L. A sparkling “dry” or “sec” carries 17 to 32 g/L, several times the sugar of a still dry wine.

Most of that sugar comes from the dosage. After disgorging, Champagne producers top up each bottle with a liqueur of cane sugar dissolved in wine, about 1 centiliter per bottle for a brut. EU law allows sucrose in this liqueur and counts it as neither enrichment nor sweetening.

German Riesling labels can carry two unrelated systems. Taste terms measure the sugar in the finished wine. Prädikat names measure how ripe the grapes were at harvest.

The German taste terms follow the EU still-wine scale: trocken (dry), halbtrocken (medium dry), lieblich (medium sweet) and süß (sweet). Feinherb is also common, and the German Wine Institute notes it has no legal definition. It usually sits in the halbtrocken to lightly lieblich range.

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Degrees Oechsle measure the density of the juice, which rises with its sugar. The minimums come from each region’s official product specification. A Kabinett or Spätlese can be dry, off-dry or sweet: the Prädikat says how ripe the grapes were, and the taste term, when there is one, says how much sugar stayed in the wine. Prädikat wines may not be chaptalized.

The VDP, the association of German top estates, calls the dry wines from its best sites Grosses Gewächs. Since the 2006 vintage they have a maximum of 9 g/L of sugar. Its sweet wines from the same sites carry the Prädikat names.

The International Riesling Foundation created a scale for the back label of any Riesling. It uses the ratio of sugar to acidity, adjusted for pH:

A wine with 12 g/L of sugar and 12 g/L of acidity counts as dry on this scale. A high pH moves a wine one step sweeter, a low pH one step drier.

• Alsace: since the 2021 vintage, white AOC Alsace must show its sugar term on the label: sec, demi-sec, moelleux or doux. Vendanges Tardives and Sélection de Grains Nobles are exempt.
• Vouvray: a dry still Vouvray must say sec on the label. Its rules allow up to 8 g/L of sugar, with the same acidity condition as the EU dry rule.
• Tokaji Aszú: at least 120 g/L of sugar.
• Pedro Ximénez sherry: more than 212 g/L.

Even an extra dry Port holds at least 17.5 g/L, more than four times the limit for a dry still wine.

Sugar goes into wine in four legal ways, and only some of them make the wine sweeter.

• Chaptalization: sugar added before or during fermentation to raise the alcohol. The yeast ferments it, so it does not sweeten the wine. The EU allows it in cooler zones, up to 3% more alcohol in zone A, 2% in zone B and 1.5% in zone C. Italy, Spain, Portugal, Greece and Cyprus may not use beet or cane sugar; they can enrich only with concentrated grape must. The US allows sugar up to a juice density of 25 degrees Brix. California bans sugar in grape wine except in sparkling wine and a few special categories.
• Sweetening after fermentation: in the EU, only grape must or concentrated grape must may sweeten a still wine, not sugar. In Germany this is called Süssreserve. US federal law allows sugar after fermentation.
• Dosage in sparkling wine: cane sugar dissolved in wine, added after disgorging. Brut nature wines skip it.
• Fortification: Port, Pedro Ximénez and vins doux naturels get grape spirit, not sugar. Their sweetness is the grape’s own sugar that the spirit kept from fermenting.

Natural wine charters forbid additives, and that rules out added sugar. The French Vin Méthode Nature charter forbids all oenological additives and any change to the chemical makeup of the grapes. Spain’s association of natural wine producers, PVN, puts it as “grapes and nothing else.” A natural wine that tastes sweet gets its sweetness from the grapes, as in the Clairette de Die and the cartagène pictured above.

• United States: no sugar or sweetness statement is required. A producer may add a voluntary nutrition statement.
• European Union: since December 8, 2023, wine must carry a nutrition declaration that includes sugars per 100 mL. The front label may show only the energy value and move the rest behind a QR code.
• Sparkling wine anywhere in the EU must carry one of the sugar terms above. On still wine the term is optional, except where an appellation requires it, as in Alsace, Vouvray and Tokaj.

Why is most wine dry?

Yeast ferments the sugar in grape juice into alcohol, and a fermentation left to finish usually leaves under about 2 g/L of sugar. A wine stays sweet only when the yeast is stopped or cannot finish.

How much sugar is in a dry wine?

Under EU law, up to 4 g/L, or up to 9 g/L when the wine’s acidity is no more than 2 g/L below the sugar. A wine fermented to the end usually has under about 2 g/L.

Is brut Champagne sweet?

Brut means under 12 g/L of sugar. Brut nature and extra brut are drier. Extra dry, sec and demi-sec are sweeter than brut.

Is Riesling sweet?

Riesling can be dry or sweet. On a German label, trocken means dry. Kabinett, Spätlese and Auslese describe how ripe the grapes were at harvest, not how sweet the wine is.

Does wine have added sugar?

Some does. Sparkling wine usually gets a dosage of sugar dissolved in wine. Chaptalization adds sugar before fermentation, but the yeast turns it into alcohol. In the EU, still wine can be sweetened only with grape must.

Does natural wine have added sugar?

Not under the natural wine charters. The French Vin Méthode Nature charter and Spain’s PVN forbid additives, which rules out added sugar. Sweet natural wines get their sweetness from the grapes.

• UC Davis: wine fermentation overview
• UC Davis: problem fermentations
• Australian Wine Research Institute: predicting alcohol levels
• Walker et al. (2022): fructose utilization by wine yeast
• Pigeau et al. (2007): yeast in Riesling ice wine juice
• Cretin et al. (2018): ethanol and sweet taste in dry wine
• EU: Delegated Regulation (EU) 2019/33, Annex III
• EU: Delegated Regulation (EU) 2019/934, Annexes I and II
• EU: Regulation (EU) 1308/2013, Annex VIII
• Comité Champagne: dosage
• German Wine Institute: taste terms
• Germany: Mosel product specification
• Germany: Baden product specification
• VDP: classification
• International Riesling Foundation: Riesling Taste Profile (archived)
• Alsace: sugar term on the label
• INAO: Vouvray specification
• Wines of Tokaj: Aszú
• IVDP: Port color and sweetness
• Consejo Regulador Jerez: Pedro Ximénez
• US: 27 CFR 24.177, chaptalization
• US: 27 CFR 24.179, sweetening
• California: 17 CCR 17010
• US: 27 CFR 4.32, mandatory label information
• EU: Regulation (EU) 2021/2117, wine labeling
• Vin Méthode Nature charter
• PVN, Asociación de Productores de Vinos Naturales