- a method of producing sparkling wines quickly and cheaply by causing secondary fermentation in a large sealed tank rather than by the classic méthode champenoise of secondary fermentation within the original glass bottle. In the US wines made in this way must state it on the label. The method is widely used to produce spumante sparkling wine in Italy. For example, Asti Spumante wine is made using a version of the Charmat process in which the grape must is stored at a very low temperature in sealed tanks so that fermentation cannot begin. The must is warmed gently and yeast is introduced to start fermentation, and the carbon dioxide produced during fermentation is retained in the sealed tanks. Once the wine has the correct sugar and alcohol levels, it is rapidly chilled to stop fermentation, then filtered, bottled and corked ready to be sold.