Charmat Method

The method carries two inventors' names, and the sources credit them differently. Decanter's James Button (2021) writes that Federico Martinotti, from the province of Asti, invented the tank method for controlled fermentation in large vats in 1895, and that fifteen years later Eugène Charmat developed the autoclave design that is still used today. A 2016/2017 writing-competition guest article on jancisrobinson.com 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 says Charmat refined and patented the invention, "so in the wine books he is the guy." The EU register text for the Asti PDO (C/2024/7280) states that by 1895 the Charmat method, which it says was invented in Piedmont, had been honed. In Italy, the Prosecco DOC disciplinare calls the process the metodo "Martinotti".

• Decanter (James Button, 2021): Federico Martinotti, from the province of Asti, invented the tank method in 1895
• Decanter (2021): fifteen years later, Eugène Charmat developed the autoclave design that is still used today
• The Prosecco DOC disciplinare describes the metodo "Martinotti" as 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. 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, in Decanter's description of Asti production. The AWRI describes the wine being 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, as the AWRI explains, headspace CO2 counter-pressure keeps the carbon dioxide from the second fermentation in solution.

• The AWRI (2025) gives processing conditions for tank sparkling wine of 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
• The Prosecco DOC disciplinare requires an elaboration period of at least 60 days in autoclave for Prosecco Spumante Rosé

The Prosecco DOC disciplinare requires Prosecco Spumante and Spumante Rosé to 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, along with German Sekt made from Riesling and Australian sparkling Shiraz. By contrast, WSET lists Champagne, Franciacorta, Trento DOC and Cava among 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: Decanter (2021) notes that the grape must is fermented only once, absorbing some of its carbon dioxide in pressurised autoclaves; WSET says Asti Spumante and Moscato d'Asti often involve just one fermentation
• WSET lists Glera (Prosecco), Moscato, Riesling and the various Lambrusco grapes as common tank method varieties
• WSET names German Sekt made from Riesling and Australian sparkling Shiraz as tank method wines made outside Italy

WSET describes tank method wines as 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 WSET links to lees autolysis in traditional method wines. The Prosecco DOC disciplinare describes 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.

• WSET: little or no lees ageing, with the focus on primary fruit and aromatic freshness
• WSET: softer bubbles and a more approachable style than traditional method wines
• Prosecco DOC disciplinare: white flowers, apple, pear, exotic fruit and citrus
• The jancisrobinson.com guest article says the system suits 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, WSET explains, 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. WSET adds that 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 (WSET)
• Traditional method lees autolysis gives brioche, toast, pastry and cream aromas; the tank method preserves primary fruit and aromatic freshness (WSET)
• EU minimum production time for PDO quality sparkling wines: six months with fermentation in closed tanks, nine months with fermentation in bottle
• WSET: 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 2026-09-25