An UCO research team is studying the effect of carbon dioxide pressure on yeast metabolism during the second fermentation of sparkling wines
During alcoholic fermentation, yeasts turn sugar into ethanol and CO2gas. The gas forms the small bubbles which distinguish sparkling wines from “still” wines. High-quality sparkling wines are made using the traditional method, which requires a second alcoholic fermentation of a base wine – to which sugar and yeasts are added – in sealed bottles, followed by an interval of ageing in contact with yeast lees. This method was first described by the Benedictine monk Dom Pierre Pèrignon (1638-1715). When sugar is added to a wine and a second fermentation is carried out in an open container, the C02 produced is released into the atmosphere; however, when the second fermentation is carried out in a sealed container or bottle, the CO2overpressure released affects yeast metabolism.