A process utilised in the production of sparkling wine (most notably in wines produced via the méthode traditionelle) whereby yeast and sugars are added to a still, (usually) dry wine and the bottle is sealed, allowing the carbon dioxide produced to be captured and dissolved back in the wine, creating bubbles on opening. The secondary fermentation increases the alcoholic content of the wine by approximately 1-1.5%. Secondary fermentation is used in other sparkling wine production techniques, such as the transfer method, but it is not employed on a bottle by bottle basis.
