Charmat Method

The method carries two inventors' names, and the sources credit them differently. Decanter's James Button credits Federico Martinotti, from the province of Asti, with inventing the tank method for controlled fermentation in large vats in 1895, and Eugène Charmat with developing, fifteen years later, the autoclave design that is still used today. A 2016/2017 writing-competition guest article on Jancis Robinson's website gives the same 1895 date for Martinotti's re-fermentation method, which added sugars and yeasts to the base wine in large closed vats, and credits Charmat with refining and patenting the invention: "so in the wine books he is the guy." The EU register text for the Asti PDO (C/2024/7280) records that by 1895 the Charmat method, invented in Piedmont, had been honed. In Italy, the Prosecco DOC disciplinare calls the process the metodo "Martinotti".

• Decanter's James Button credits Federico Martinotti, from the province of Asti, with inventing the tank method in 1895
• Fifteen years later, Eugène Charmat developed the autoclave design that is still used today
• The metodo "Martinotti" of the Prosecco DOC disciplinare is natural re-fermentation of the base wine in large vessels or autoclaves
• Naming varies by source: Decanter uses "Martinotti-Charmat method", and WSET uses "tank method (also known as the Charmat method)"

The Charmat Method begins with a still base wine that is transferred into a large, sealed stainless steel autoclave along with added yeast and sugar to trigger secondary fermentation. Under EU rules, the carbon dioxide in a sparkling wine may come only from the alcoholic fermentation of the cuvée, and that fermentation may take place only in bottles or in closed tanks. For PDO quality sparkling wines, EU rules require at least 90 days of fermentation and presence on the lees, or 30 days if the fermentation takes place in containers with stirrers, and at least six months of total production time when the fermentation takes place in closed tanks. In Asti production, once the desired alcohol level is reached, the autoclave is chilled to stop fermentation and the wine is filtered to remove the yeast before bottling. For tank-fermented sparkling wine, the wine is filtered under isobaric conditions into a filtrate tank pressurised with CO2 to match the ferment tank, then bottled, with CO2 added to replace the wine as it leaves each tank, at processing temperatures of around 0°C. Filtration and bottling run under CO2 counter-pressure to retain carbonation, because headspace CO2 counter-pressure keeps the carbon dioxide from the second fermentation in solution.

• Processing conditions for tank sparkling wine may be around 270 kPa-g and around 0°C
• EU rules require at least six months of total production for PDO quality sparkling wines fermented in closed tanks, against nine months for those fermented in bottle
• For quality aromatic sparkling wines, EU rules allow the fermentation to be controlled only by refrigeration or other physical processes and set a minimum production process of one month
• Prosecco Spumante Rosé needs an elaboration period of at least 60 days in autoclave

Under the Prosecco DOC disciplinare, Prosecco Spumante and Spumante Rosé must be made exclusively by natural fermentation in autoclave, while Prosecco Frizzante may be made in bottle or in autoclave. WSET calls Prosecco the most widely recognised tank method sparkling wine and names Asti Spumante and Moscato d'Asti as other important tank method styles. Tank method wines are also made outside Italy, including German Sekt made from Riesling and Australian sparkling Shiraz. By contrast, Champagne, Franciacorta, Trento DOC and Cava are traditional method wines, made with a second fermentation inside the bottle.

• Prosecco DOC: Spumante and Spumante Rosé exclusively by natural fermentation in autoclave; Frizzante in bottle or in autoclave (disciplinare, Article 5)
• Asti: in Decanter's account the grape must is fermented only once, absorbing some of its carbon dioxide in pressurised autoclaves; WSET puts it more loosely, with Asti Spumante and Moscato d'Asti often involving just one fermentation
• Common tank method varieties include Glera (Prosecco), Moscato, Riesling and the various Lambrusco grapes
• German Sekt made from Riesling and Australian sparkling Shiraz are tank method wines made outside Italy

Tank method wines are typically light, fresh and fruit-driven, with softer bubbles and a more approachable style. Because they spend little or no time ageing on lees, the focus is on preserving primary fruit and aromatic freshness rather than the brioche and toast aromas that lees autolysis gives traditional method wines. The Prosecco DOC disciplinare lists floral notes of white flowers and fruit notes of apple, pear, exotic fruit and citrus. Pressure is set by wine category, not by method: EU rules require an excess pressure of at least 3.5 bar at 20°C for quality sparkling wine and at least 3 bar for sparkling wine and quality aromatic sparkling wine.

• Little or no lees ageing, with the focus on primary fruit and aromatic freshness
• Softer bubbles and a more approachable style than traditional method wines
• Prosecco DOC disciplinare: white flowers, apple, pear, exotic fruit and citrus
• A writing-competition guest article on Jancis Robinson's website judges the system good for aromatic and semi-aromatic grape varieties, because it boosts aromas, delicacy and freshness more than structure

The difference lies in where the second fermentation takes place. In the traditional method, the second fermentation happens inside the bottle and is followed by ageing on the lees, whose autolysis releases aromas such as brioche, toast, pastry and cream. In the tank method, the second fermentation happens in a sealed stainless-steel tank and the wine spends little or no time on lees. Tank method wines are generally more affordable due to faster production and lower labour requirements.

• Tank method: second fermentation in a sealed stainless-steel tank; traditional method: second fermentation inside the bottle
• Traditional method lees autolysis gives brioche, toast, pastry and cream aromas; the tank method preserves primary fruit and aromatic freshness
• EU minimum production time for PDO quality sparkling wines: six months with fermentation in closed tanks, nine months with fermentation in bottle
• Tank method wines are generally more affordable due to faster production and lower labour requirements

Primary sources (MASAF Prosecco DOC disciplinare, EU law and register texts, WSET, AWRI): https://www.masaf.gov.it/flex/cm/pages/ServeAttachment.php/L/IT/D/1%252F1%252F2%252FD.e6818b2795e7a32f7456/P/BLOB%3AID%3D23481/E/pdf?mode=download, https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=OJ:C_202407280, https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:32019R0934, https://www.wsetglobal.com/knowledge-centre/blog/2026/a-guide-to-sparkling-wine-production-methods-and-regional-styles, https://www.awri.com.au/wp-content/uploads/2025/01/s2430.pdf, https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:32013R1308. Secondary sources: https://www.decanter.com/premium/asti-and-moscato-dasti-experts-choice-462890/, https://www.jancisrobinson.com/articles/in-praise-of-prosecco, https://italianwinecentral.com/denomination/prosecco-doc/. Last verified 2026-10-05