Charmat / Tank Method (Prosecco, Lambrusco & Beyond)

The Charmat method (also known as the Martinotti method, tank method, metodo italiano, or cuve close) is a sparkling wine production technique in which a still base wine undergoes secondary fermentation inside large sealed stainless steel tanks called autoclaves, rather than in individual bottles as in the traditional method. The process was invented and patented in 1895 by Federico Martinotti, Director of the Experimental Institute for Oenology in Asti, and later refined and separately patented by French inventor Eugène Charmat in 1907. In Italy the method is often called the Martinotti method in recognition of its Italian origins. The core principle is simple: by trapping carbon dioxide produced during fermentation inside a sealed pressurized tank, the resulting bubbles dissolve directly into the wine.

• Also called cuve close (French for sealed tank), metodo italiano, or autoclave method; all refer to the same tank-based secondary fermentation process
• Tanks operate at 2–4 atmospheres of pressure, producing a softer carbonation than the traditional method, which achieves 5–7 atmospheres
• Post-fermentation, wine is cooled, filtered to remove yeast, and bottled under counter-pressure to retain dissolved CO2
• The method made large-scale, affordable sparkling wine production commercially viable for the first time, enabling mass production of wines like Prosecco and Lambrusco

The Charmat method begins with a fully fermented, dry still base wine. This is transferred into a pressurized autoclave along with a liqueur de tirage (a mixture of wine, sugar, and selected yeast cultures) to initiate the secondary fermentation. As yeast consumes the sugar, CO2 is produced and, because the tank is sealed, dissolves into the wine rather than escaping. Temperature is carefully controlled throughout, often between 14 and 18 degrees Celsius, to manage fermentation speed and preserve delicate aromatic compounds. Once the target pressure is reached, fermentation is arrested by rapidly chilling the wine. The wine is then filtered under pressure to remove yeast cells and bottled immediately to retain its carbonation. Residence time in tank varies: Prosecco DOC requires a minimum of 30 days, while Charmat Lungo versions may remain in tank for up to 9 months.

• Liqueur de tirage (sugar and yeast mixture) initiates secondary fermentation in the sealed autoclave; sugar dose determines final pressure
• Fermentation temperature, typically 14–18°C, is controlled precisely to slow yeast activity and preserve volatile primary aromatics
• Fermentation arrest by rapid chilling stops yeast activity at the target pressure; cold stabilization follows before filtration
• Charmat Lungo is a longer-contact variant where wine rests on lees in tank for several months, developing additional texture and subtle autolytic complexity

The defining stylistic outcome of the Charmat method is the preservation of primary and secondary fruit aromatics. Because fermentation is relatively brief and yeast contact is minimal compared to the traditional method, the wine retains fresh green apple, citrus zest, white flowers, stone fruit, and herbaceous character rather than developing the brioche, toast, and nutty notes that extended autolysis brings to bottle-fermented wines. The softer carbonation of 2–4 atmospheres produces a creamier, lighter mouthfeel than the more intense effervescence of traditional method wines. Most Charmat wines are best consumed young, typically within two to three years of release, though high-quality hillside Prosecco from Valdobbiadene can reward several more years of careful cellaring.

• Dominant aromatics: green apple, pear, citrus zest, white flowers (acacia, wisteria), stone fruit (peach, apricot), and light herbaceous notes
• Minimal autolytic character: short tank contact means little brioche, toast, or nuttiness; fruity freshness is the primary profile
• Softer carbonation (2–4 atm) delivers a creamier, lighter mouthfeel compared to the more vigorous effervescence of traditional method wines at 5–7 atm
• Most Charmat wines peak within 2–3 years of release; premium hillside Valdobbiadene DOCG Prosecco can evolve positively for 5 or more years

Winemakers choose the Charmat method when volume, aromatic freshness, and cost efficiency are priorities. For Prosecco DOC and Prosecco Superiore DOCG producers, the method is mandated by appellation regulations. The Prosecco DOC alone recorded 660 million bottles in 2024, a scale of production that makes traditional bottle fermentation economically impractical. The method is also favored for aromatic grape varieties such as Glera, Moscato Bianco, and Lambrusco, where the fruit-forward and floral character the grapes naturally offer is best preserved by limited yeast contact and rapid processing. German Sekt production and many sparkling wines from the United States and other New World regions also rely on the Charmat method for similar reasons.

• Regulatory mandate: Prosecco DOC and Prosecco Superiore DOCG use Charmat as their standard production method; minimum 30 days in autoclave
• Cost efficiency: shorter production cycles and reduced labor compared to traditional method allows competitive retail pricing
• Aromatic suitability: ideal for expressive varieties like Glera, Moscato Bianco, Riesling, and Lambrusco, where primary fruit must be preserved
• Also widely used for German Sekt, many New World sparkling wines, and Asti Spumante DOCG (though the Asti method is technically a single, not secondary, fermentation)

Prosecco Superiore di Conegliano Valdobbiadene DOCG (Veneto, Italy) is the world's most celebrated Charmat category. Producers such as Bisol1542, with roots dating to 1542, and Nino Franco, a family estate since 1919, craft benchmark examples showcasing Glera's signature profile of green apple, pear, white peach, and wisteria. Lambrusco from Emilia-Romagna is another major Charmat expression: Cleto Chiarli, founded in 1860 and the first producer in the region to adopt the method, produces a wide range from dry to amabile styles using Lambrusco Grasparossa and Lambrusco di Sorbara. Moscato d'Asti DOCG and Asti Spumante DOCG from Piedmont use the related Asti method, a single continuous fermentation arrested early to preserve residual sugar, resulting in wines with maximum 5.5% ABV and up to 1.7 atmospheres pressure for Moscato d'Asti, or 3.5–4 atmospheres for Asti Spumante.

• Bisol1542 'Crede' Brut and Nino Franco 'Rustico' Valdobbiadene Prosecco Superiore DOCG: benchmark examples of Charmat's ability to express Glera's aromatic character
• Cleto Chiarli (founded 1860, Modena): pioneer of Charmat-method Lambrusco in Emilia-Romagna; portfolio spans brut, secco, and amabile styles from Lambrusco Grasparossa and Lambrusco di Sorbara
• Moscato d'Asti DOCG: single fermentation (Asti method) produces frizzante style at max 5.5% ABV and max 1.7 atmospheres; technically distinct from Charmat but also tank-based
• Asti Spumante DOCG: single fermentation arrested later than Moscato d'Asti, producing a fully sparkling wine at 7–9.5% ABV and 3.5–4 atmospheres pressure

The traditional method (méthode champenoise or metodo classico) requires secondary fermentation inside the individual bottle that will be sold to the consumer, followed by extended aging on lees, riddling, and disgorgement. This produces wines with 5–7 atmospheres of pressure, fine persistent bubbles, and complex autolytic character (brioche, toast, nuttiness) developed through prolonged yeast contact. Champagne requires a minimum of 15 months on lees for non-vintage and 36 months for vintage; Cava requires a minimum of 9 months. The Charmat method compresses the process into as little as 30 days in tank, preserving primary fruit character at the cost of autolytic complexity. Neither is inherently superior; they are suited to different grape varieties, stylistic goals, and market positions. Charmat excels at showcasing aromatic, fresh-fruited varieties, while the traditional method rewards patience and extended aging.

• Traditional method: 5–7 atmospheres, fine persistent bubbles, autolytic brioche and toast notes; minimum 15 months for non-vintage Champagne, 9 months for Cava
• Charmat method: 2–4 atmospheres, softer carbonation, vibrant primary fruit and floral aromatics; minimum 30 days for Prosecco DOC
• Autolysis contrast: traditional method produces extensive lees contact in bottle; Charmat minimizes yeast contact, explaining the freshness versus complexity trade-off
• Neither method is superior: aromatic varieties (Glera, Lambrusco, Riesling) thrive under Charmat; Chardonnay and Pinot Noir reveal their best under traditional method