The process of injecting carbon dioxide into wine to convert sugar into alcohol, an inferior process when compared to secondary fermentation in the production of sparkling wines. Secondary fermentation is a fermentation process occurring after primary fermentation. Following primary fermentation, the wine is racked (refer to "racking") to a secondary fermentation vessel, capped, and air locked. The wine is then allowed to ferment for several months. When the desired amount of sugar has converted to alcohol, the secondary fermentation is complete.