Secondary fermentation

In winemaking, a second alcohol fermentation by yeast performed in a champagne bottle secured with a special, hollow closure secured with a wire "cage," the purpose of which is to trap the carbon dioxide produced by the fermentation and force it to be absorbed into the wine. The result is a sparkling wine. This secondary fermentation can actually be a continuation of the fermentation by the original yeast inoculation or can be induced at bottling time by inoculating a sweetened still wine with a second yeast especially adept at fermenting under pressure. It is NOT correct to refer to a fermentation in a secondary fermentation vessel (e.g. a carboy) as a secondary fermentation. See primary fermentation and Krausening.