Champagne is made using the méthode champenoise process, in which newly made still or “base” wine is dosed with sugar and yeast, sealed in bottles and left for several weeks. During that time, a second fermentation occurs in the bottle, producing Champagne’s trademark bubbles. Many inexpensive sparkling wines are also made this way, but some less-expensive versions, such as most Proseccos, result from what’s known as the Charmat process. This alternative approach involves adding the mixture of yeast and sugar to base wine that’s stored in large, sealed tanks. Some particularly cheap sparkling wines are made with carbonation—the same procedure used for soft drinks. In general, they should be avoided.