Definition: Closed tank method (or long Charmat method)

Method for producing sparkling wines with the second fermentation of a large volume of wine in hermetically sealed vats. This method is no different from the Champagne method in the stages following alcoholic fermentation, except that the second fermentation does not take place in bottles but during a new fermentation in vats, where the still wine (the base wine) is transformed into sparkling wine. The wine is then bottled with a liqueur de tirage, as in the traditional method.