Sur Lie Aging

Lees are the sediments deposited at the bottom of a vessel: mostly dead yeast cells, which naturally settle to the bottom of the fermentation vessel during and after fermentation. Fermentation lees are primarily made up of yeast cells, tartaric acid salts, bacteria, phenolic material and remnant grape solids. Winemakers generally distinguish between gross and fine lees. Gross lees are the larger particles, including yeast cells and grape matter such as pieces of skin, stem and seed, and can lead to the development of undesirable aromas and flavors; fine lees are smaller, take longer to settle, and are the ones associated with a desirable impact on the finished wine. Gross lees tend to settle naturally and are generally separated from the wine quite quickly. When wine is left on its fine lees, the dead yeast cells go through autolysis: their internal structures are destroyed by their own enzymes. This self-destruction releases a spectrum of compounds into the wine, including mannoproteins, polysaccharides, amino acids, and fatty acids. Yeast cell components reach the wine through both passive transfer from the cells and autolysis, and amino acids, polysaccharides, mannoproteins and fatty acids are the most important yeast-derived compounds for improving a wine's sensory properties. Mannoproteins reduce tartrate precipitation and promote protein stability.

• Gross lees are generally separated from the wine quite quickly; fine lees are the ones associated with a desirable impact on the finished wine.
• Fine lees are smaller particles that take longer to settle and interact with other compounds in the wine.
• Lees contact is credited with increased texture, greater oak, fruit and yeast integration, and more complexity.
• Mannoproteins reduce tartrate precipitation and promote protein stability.

Autolysis is the breakdown of dead yeast cells by their own enzymes. In traditional method sparkling wine, the lees break down over time in this way, releasing aromas such as brioche, toast, pastry and cream. The longer a traditional method wine remains on its lees, the more intense and complex its brioche, toast, pastry and cream aromas become. Acacia, oatmeal biscuit, brioche, bread dough and toasted nuts are telltale flavors of sur lie ageing, and autolysis releases sugars and peptides that contribute to an unctuous, buttery mouthfeel. Lees also protect the wine. Lees can scavenge oxygen entering through the barrel staves and the bunghole, especially when they are stirred, which can mean lower concentrations of SO2 are needed to prevent oxidation. Lees also serve as micronutrients for the lactic bacteria that carry out malolactic fermentation. Depending on the producer's preferred style, lees contact can last anywhere from a few weeks to several years.

• Lees can scavenge oxygen entering a barrel, especially when stirred, which can reduce the SO2 needed to prevent oxidation.
• The longer a traditional method wine remains on its lees, the more intense and complex its autolytic aromas become.
• Acacia, oatmeal biscuit, brioche, bread dough and toasted nuts are telltale flavors of sur lie ageing.
• Lees serve as micronutrients for the lactic bacteria that perform malolactic fermentation.

Sur lie aging is most closely associated with traditional method sparkling wines, white Burgundy, and Muscadet. In Champagne, the process occurs in bottle following secondary fermentation. Under the 2019 AOC Champagne specification, disgorgement is not allowed until twelve months after tirage, during which the wine must stay in bottle without interruption, and minimum cellar ageing is 15 months for non-vintage and 36 months for vintage Champagne. Vintage Champagne requires a minimum of 3 years on lees; in practice, vintage Champagne is nearly always matured for 4 to 10 years, and non-vintage for 2 to 3 years. In Cava, the ageing categories run from a minimum of 9 months in bottle for Cava de Guarda, through 18 months for Cava Reserva and 30 months for Gran Reserva, up to 36 months for Cava de Paraje Calificado, whose 36 months are spent ageing on the lees. Franciacorta Riserva requires a minimum of 60 months on lees. For still wines, Muscadet Sèvre-et-Maine wines are aged on their fine lees at least until 1 March and until shipment, and the 'sur lie' mention is reserved for wines bottled in the cellars where they were made before 31 December. The Muscadet Sèvre-et-Maine crus communaux, such as Clisson, Monnières-Saint-Fiacre and Gorges, are aged 18 to 36 months on lees. The 2018 specification for the regional AOC Muscadet also provides for the 'sur lie' mention: such wines spend only one winter in vat or barrel and are still on their fine lees when bottled. The rules for the traditional 'sur lie' mention date to 1977. White Burgundy is aged sur lie in barrel: barrel lees contact is most commonly associated with Burgundian Chardonnay and Muscadet, and Burgundy and Burgundy-inspired Chardonnays around the world are among the wines that owe their identity to lees ageing, though stirring is not applied everywhere (see the bâtonnage section).

• Champagne: disgorgement no earlier than 12 months after tirage; release after at least 15 months (non-vintage) or 36 months (vintage) of cellar ageing.
• Muscadet Sèvre-et-Maine: on fine lees at least until 1 March; 'sur lie' wines are bottled in the cellars of vinification before 31 December.
• Cava ageing categories run from 9 months (Cava de Guarda) to 36 months (Cava de Paraje Calificado); Franciacorta Riserva requires 60 months on lees.
• The regional AOC Muscadet name may be completed by the mention 'sur lie' for wines that meet the conditions set for it.

In traditional method sparkling wine, lees aging takes place inside the bottle. The wine undergoes a second fermentation inside the bottle, followed by ageing on the lees: as fermentation finishes, the yeast cells die and form lees. In Champagne, the bottles are then taken down to the cellars where, undisturbed and protected from the light, they mature on lees. The yeasts die and decompose (autolysis), while minute quantities of oxygen enter the bottle and small amounts of carbon dioxide escape, leading to slow oxidation of the wine. A steady temperature of around 12°C is crucial for the best ageing conditions. Lees help limit oxidation and create a generally reductive environment, and extended lees ageing in bottle (late disgorgement) is sometimes associated with greater ageing potential and more complex aromas, while also helping to preserve freshness for longer. At the end of the aging period, riddling (remuage) is used to consolidate the lees sediment in the neck of the bottle, after which disgorgement removes the lees before the wine is finished and sealed for release. A small amount of wine and sugar, the dosage, is added before the bottle is sealed again.

• Traditional method sparkling wines undergo a second fermentation in the bottle, followed by ageing on the lees.
• A steady cellar temperature of around 12°C is crucial for lees maturation.
• Riddling collects the sediment in the neck of the bottle; disgorgement then removes it before the dosage is added and the bottle is sealed again.
• Tank method wines spend little or no time ageing on lees, with the focus on preserving primary fruit and aromatic freshness.

Barrel lees contact is most commonly associated with Burgundian Chardonnay and Muscadet, and the periodic stirring of the lees in barrel, known in French as bâtonnage, is often performed, although the practice has pros and cons. By increasing the contact surface between wine and lees, bâtonnage encourages greater unctuosity and lees-derived aromas; it also ensures homogenous contact with the lees and prevents the accumulation of hydrogen sulfide. Lees can scavenge oxygen especially when they are stirred, but excessive stirring can introduce too much oxygen, leading to the loss of SO2 and potentially the formation of acetaldehyde and acetic acid. Bâtonnage is not universal: Jean-Charles Thomas, winemaker at Maison Louis Latour, considers that lees ageing and stirring give pretty much the same result and that the choice is essentially stylistic, and no or very little bâtonnage is practised at Maison Louis Latour. In Champagne, the bottles mature undisturbed on their lees until riddling and disgorgement.

• Bâtonnage increases the contact surface between lees and wine, encouraging greater unctuosity and lees-derived aromas.
• Stirring prevents the accumulation of hydrogen sulfide and helps lees scavenge oxygen.
• Excessive stirring can introduce too much oxygen, with loss of SO2 and potential acetaldehyde and acetic acid formation.
• At Maison Louis Latour, no or very little bâtonnage is practised; its winemaker calls the choice between stirring and resting essentially stylistic.

Lees ageing can lead to unwanted volatile sulfur compounds (VSCs), which are more likely to form in wines fermented in tank, because of the relatively lower oxygen concentration, or when insufficient oxygen is introduced by stirring. That is why lees ageing is most commonly performed in small oak barrels. For tank-fermented wines, the problem can be largely negated by storing the lees in barrels for a few days and later recombining them with the wine. Other risks include 'leesy' and 'cheesy' sensory characters, unwanted VSCs when initial juice solids are above 200 NTU, and acetaldehyde and acetic acid when stirring and topping introduce excessive oxygen. In one study of Chardonnay kept on lees for 180 days, tyramine and histamine concentrations were higher than in the same wine stored in barrels without lees, particularly when the wine was stirred. Stylistic fit matters too. Where the aim is primary fruit, as in tank method sparkling wines, lees time is short: tank method wines spend little or no time ageing on lees, the focus being on preserving primary fruit and aromatic freshness. In a 2008 barrel-fermented Chardonnay trial by Brajkovich, the wine that was neither stirred nor topped was preferred after four months and described as fresher and with more varietal definition. Ageing on the lees requires technical knowledge and an acknowledgment of the desired style of wine.

• Unwanted VSCs are more likely to form when initial juice solids are above 200 NTU or when stirring introduces insufficient oxygen.
• Lees ageing is most commonly performed in small oak barrels; lees from tank-fermented wines can be stored in barrels for a few days and recombined with the wine.
• In a 2008 Chardonnay trial by Brajkovich, the wine that was neither stirred nor topped was preferred after four months as fresher and with more varietal definition.
• Tyramine and histamine were higher in a Chardonnay kept on lees for 180 days than in the same wine without lees, particularly when stirred.

Primary sources (the Australian Wine Research Institute, the Comité Champagne, the INAO, InterLoire and WSET): https://www.awri.com.au/industry_support/winemaking_resources/winemaking-practices/winemaking-treatment-lees-contact/, https://www.champagne.fr/en/about-champagne/how-champagne-is-made/maturation, https://extranet.inao.gouv.fr/fichier/PNOCDCAOC-Champagne-20190619.pdf, https://www.champagne.fr/system/files/2025-09/FICHE%20AOC%20CHAMPAGNE%20EN%202025.pdf, https://www.inao.gouv.fr/node/37679/printable/print, https://extranet.inao.gouv.fr/fichier/CDC-Muscadet-PNO.pdf, https://www.vinsdeloire.fr/fr/vins-loire/muscadet-sevre-et-maine, https://www.wsetglobal.com/knowledge-centre/blog/2026/a-guide-to-sparkling-wine-production-methods-and-regional-styles. Secondary: https://www.decanter.com/learn/what-is-sur-lie-ageing-and-what-does-it-do-to-wine-ask-decanter-465202/, https://www.decanter.com/learn/advice/what-are-lees-in-wine-ask-decanter-377513/, https://www.decanter.com/learn/advice/lees-ageing-batonnage-taste-353099/, https://www.decanter.com/sponsored/is-this-a-bottle-of-d-o-cava-513546/. Last verified 2026-10-04