The bubbles in sparkling wine are formed when the base wine undergoes a secondary fermentation, trapping carbon dioxide inside the bottle or fermentation vessel. Champagne, Cava and many other sparkling wines (particularly in the New World) are made using the ?traditional method,? in which the second fermentation takes place inside the bottle. With this method, spent yeast cells remain in contact with the wine during bottle aging, giving it a creamy mouthful and toasted bread or brioche qualities. For Prosecco, the carbonation process occurs in a stainless steel tank to preserve the fresh fruity and floral aromas preferred for this style of wine.
