Charmat

What is Charmat? Charmat is a sparkling-wine production method in which the secondary fermentation takes place inside large, sealed stainless-steel pressure tanks rather than in individual bottles. The technique was first patented in 1895 by Italian winemaker Federico Martinotti and further refined and re-patented in 1907 by the French inventor Eugène Charmat, which is why it is also known as Metodo Martinotti, Metodo Italiano, Cuve close, or simply the tank method. Today it is the standard process behind Prosecco, Asti, Lambrusco, and a wide range of other aromatic sparkling wines around the world.

How the Method Works

The process begins with a finished base wine that is transferred into a pressurized stainless-steel tank called an autoclave. Winemakers add sugar and yeast to trigger a second fermentation, and because the tank is hermetically sealed, the carbon dioxide produced by the yeast cannot escape. Instead, it dissolves into the wine itself, which is precisely what creates the bubbles.

Once the secondary fermentation is complete, the spent yeast is filtered out and the carbonated wine is moved under pressure directly into bottles, ready for sale. The length of the tank fermentation is one of the most important quality variables: longer fermentations tend to preserve aromatics more faithfully and yield finer, more persistent bubbles, while shorter ones favor scale and freshness over complexity.

Charmat vs. the Traditional Method

The defining difference between Charmat and the traditional method (also known as methode champenoise or metodo classico) is where the second fermentation happens. In the traditional method it takes place inside the same bottle the consumer eventually opens, which requires labor-intensive riddling and disgorgement. Charmat skips both of those steps entirely, making it faster, more scalable, and significantly less expensive to produce.

The two methods also pursue different flavor goals. Charmat is generally preferred for aromatic grape varieties such as Glera in Prosecco and Moscato in Asti, because the shorter tank process protects the primary fruit and floral character of the grape. The traditional method, by contrast, emphasizes the autolytic, yeasty, bready notes that come from extended contact with lees in the bottle.

Wines Made This Way

The most famous expressions of the Charmat method come from Italy: Prosecco from the Veneto and Friuli, Asti and Asti Spumante from Piedmont, and the lightly sparkling reds of Lambrusco in Emilia-Romagna. Each of these styles owes its bright, fruit-forward profile to the tank fermentation that defines the technique.

Beyond Italy, the method underpins many German Sekt brands such as Henkell Trocken and is widely used in the United States and other producing countries for accessibly priced sparkling wines. When freshness, aromatics, and value matter more than the toasty complexity of bottle-aged sparklers, Charmat is the method of choice.