Fermentation alcoolique

In the traditional and tank methods it happens twice. The first fermentation turns settled must into still base wine, the vin clair; it can be carried out in oak but usually takes place in stainless steel vats.²

The second, the prise de mousse, takes place in a closed bottle or tank so the CO2 stays in the wine.³ Fermenting the tirage sugar raises alcohol by roughly 1.2-1.3 degrees.⁴ Asti spumante uses a single fermentation in autoclave (Asti method).⁵ See first fermentation.