Why are there bubbles in beer and champagne? Solution Bubbles of gas, typically carbon dioxide are produced from beer and champagne , rising to the surface. Because . yeasts ferment sugars and form carbon dioxide gas during fermentation. In the bottle, where the pressure is high, the carbon dioxide disappears. However, when you open the bottle and lower the pressure, the carbon dioxide escapes in the form of bubbles. In Champagne and other sparkling wines, the bubbles pop, while in beer, the bubbles remain and form the beer\'shead..