Prise de Mousse and Autolysis

Prise de mousse, literally capturing the fizz, is the name used in Champagne for the second fermentation carried out in the bottle, when the wine becomes sparkling. To control the prise de mousse, Champagne makers introduced double fermentation known as the Méthode Champenoise. The second fermentation is triggered by the liqueur de tirage, a solution of yeasts, sugar and wine that is added to the cuvée, and the wine is sealed in bottle with a crown cap. Fermentation is the work of yeasts, living micro-organisms that transform sugars into alcohol and carbon dioxide. Inside the sealed bottle the carbon dioxide becomes trapped and forms the bubbles. The AOC Champagne specification requires the wines to be made exclusively by second fermentation in glass bottles, and tirage into the bottles where the prise de mousse takes place cannot happen before 1 January of the year after the harvest. After the prise de mousse, the wines must contain 10 grams per litre or less of fermentable sugars (glucose and fructose). Research papers give a sense of scale, though their figures are not Champagne rules. An OENO One paper on Auxerrois sparkling wines by Wilson, Charnock, Xu and Kemp states that the second fermentation requires 22 to 23 g/L of sucrose, which achieves approximately six atmospheres of pressure in the finished wine, citing earlier work by Kemp and colleagues. A 2023 OENO One study by Cisilotto and colleagues suggests that in this fermentation just 20 to 25 g/L of sugar is consumed, giving 1 to 1.5 % (v/v) ethanol. The Comité Champagne gives the pressure inside a Champagne bottle as "within the range of 5 to 6 bar." The OIV defines sparkling wine as having an excess carbon dioxide pressure in the bottle of at least 3.5 bars at 20°C (3 bars for bottles under 0.25 l). Today's Champagne bottles have been designed to withstand a pressure of 20 bar, which the Comité Champagne calls "three times the natural pressure of Champagne." A bottle of Champagne tends to be about 12% alcohol.

• Prise de mousse: the second fermentation, in the bottle, when the wine becomes sparkling (literally capturing the fizz)
• Liqueur de tirage: yeasts, sugar and wine, added to trigger the second fermentation; the bottle is sealed with a crown cap
• AOC Champagne: second fermentation exclusively in glass bottles; tirage not before 1 January of the year after the harvest; 10 g/L or less of fermentable sugars after the prise de mousse
• Research figures: an OENO One paper (Wilson et al.) states 22 to 23 g/L of sucrose for approximately six atmospheres; a 2023 OENO One study (Cisilotto et al.) suggests 20 to 25 g/L of sugar consumed for 1 to 1.5 % (v/v) ethanol
• Pressure: Comité Champagne, within the range of 5 to 6 bar inside a bottle; OIV sparkling wine minimum of 3.5 bars excess pressure at 20°C; Champagne bottles designed to withstand 20 bar

As the second fermentation finishes, the yeast cells die and form lees, which are essentially deposits of dead yeast cells. Autolysis is the enzymatic degradation (hydrolysis) of yeast cell constituents after cell death: the dead cells' internal structures are destroyed by their own enzymes. Autolytic character develops slowly. Decanter notes that, if managed correctly, ageing wine in contact with its lees can add flavour, textural and structural benefits: the process releases sugars and peptides that will contribute to an unctuous, buttery mouthfeel, and the wine becomes chemically more stable, with mannoproteins reducing tartrate precipitation and promoting protein stability. The tank method, also known as the Charmat method, also involves a second fermentation, but it takes place in large-volume pressure tanks, usually made of stainless steel, and unlike traditional method wines, tank method wines spend little or no time ageing on lees. One study questions how much the method itself matters. A 2023 OENO One study by Cisilotto and colleagues compared Traditional and Charmat sparkling wines made with the same base wine, yeast strain and inoculum and aged on the lees for the same periods, found no evident differences in physicochemical and volatile compounds, and concluded that the method used for the second fermentation is not the determinant of the eventual differences.

• Lees: essentially deposits of dead yeast cells, formed as the second fermentation finishes
• Autolysis: enzymatic degradation (hydrolysis) of yeast cell constituents after cell death; autolytic character develops slowly
• Per Decanter, when managed correctly, lees ageing can add benefits: released sugars and peptides contribute to an unctuous, buttery mouthfeel; mannoproteins reduce tartrate precipitation and promote protein stability
• Tank (Charmat) method: second fermentation in pressure tanks; little or no time ageing on lees

Over time, autolysis releases aromas such as brioche, toast, pastry and cream, and the longer the wine remains on its lees, the more intense and complex these flavours become. A 2026 OENO One paper by Maury and colleagues on still Chenin blanc wines summarises earlier research in its introduction: contact between wine and lees leads to increased roundness and fullness, and wines aged on lees are richer in polysaccharides, particularly mannoproteins. The same paper notes that ageing on lees also induces a release of free amino acids in wine, and that a few amino acids have been reported to underlie the perception of umami in beverages like tea, sake and Champagne.

• Autolysis aromas: brioche, toast, pastry and cream
• More time on the lees: more intense and complex flavours
• Lees contact and texture: increased roundness and fullness; wines richer in polysaccharides, particularly mannoproteins (OENO One, Maury et al. 2026, introduction)
• Free amino acids: released into wine during ageing on lees (OENO One, Maury et al. 2026, still Chenin blanc)

Under the AOC Champagne specification (cahier des charges, decree of 22 November 2010), non-vintage Champagne may be released to consumers only after an ageing period of at least 15 months from the date of tirage, and vintage Champagne only after at least 36 months from the date of tirage. Disgorgement cannot take place before 12 months from the date of tirage, a period during which the wines must stay in bottle without interruption. The Comité Champagne gives the same minimums: at least 15 months for non-vintage wines and at least 3 years for vintage wines, from the date on which they are bottled. Once lees ageing is complete, the bottles are riddled to collect the sediment in the neck, then disgorged, ejecting the lees that have collected there.

• Non-vintage: at least 15 months from tirage before release (AOC Champagne)
• Vintage: at least 36 months from tirage before release (AOC Champagne)
• Disgorgement: not before 12 months from tirage, with the wine in bottle without interruption
• After lees ageing: riddling collects the sediment in the neck, then disgorgement ejects the lees

Primary sources (AOC Champagne cahier des charges via eAmbrosia; Comité Champagne): https://webgate.ec.europa.eu/eambrosia-api/api/v1/attachments/8209, https://www.champagne.fr/en/champagne-frequently-asked-questions, https://www.champagne.fr/en/about-champagne/a-great-blended-wine/champagne-bottles-bottling, https://www.champagne.fr/en/glossary. Secondary sources (Decanter, WSET, OIV, AWRI): https://www.decanter.com/learn/what-is-sur-lie-ageing-and-what-does-it-do-to-wine-ask-decanter-465202/, https://www.wsetglobal.com/news-insights/insight-opinion/a-guide-to-sparkling-wine-production-methods-and-regional-styles/, https://www.oiv.int/node/2172/download/pdf, https://www.awri.com.au/wp-content/uploads/2018/08/Novel-sparkling-winemaking-technologies-and-visualising-yeast-autolysis.pdf. Journal sources (OENO One; named, hedged findings): https://oeno-one.eu/article/view/7313, https://oeno-one.eu/article/download/4864/27945, https://oeno-one.eu/article/download/8403/51423. Last verified 2026-11-09