Charmat Process (Tank Method, Bulk Method)
This process is considered less labor intensive than the traditional method, as it does not involve a second alcoholic fermentation in individual bottles and disgorgement. Some may consider the Charmat process an “inferior” way to make sparkling wine. However, the Charmat process is traditionally used in sparkling wine production of aromatic varieties (e.g., Chenin Blanc, Riesling, Muscat, Gewurztraminer, etc.) to avoid heavy contact with yeast lees that are otherwise available through méthode Champenoise processing. Extended lees contact could easily mask the natural fruity aromas and flavors produced by the grape. Commercially, this method could be applied to a number of grape varieties and it is used to produce several quality sparkling wine styles.
In the Charmat method, after the base wine cuvée is established, it is transferred into a cold, pressurized tank instead of a bottle. Yeast and sugar are added to the tank to undergo a second alcoholic fermentation under pressure, which ensures the retention of carbon dioxide. As the surface area of yeast-to-wine is a lot less than in the traditional method, the autolytic yeast character is not as prevalent in these wines. Once the second fermentation is complete, the wine is filtered and transferred to a second cold, pressurized tank that contains the dosage for the entire batch of wine. Wine is bottled from the tank. Examples of commercial wines that utilize the Charmat method include Prosecco (Italy) and Sekt (Germany).