For starters, the beer that goes into casks is unfiltered and unpasteurized. This means that live yeast remains in the liquid, causing it to undergo a secondary fermentation in the cask itself.

Selecting Yeast in Beer Brewing and Wine Making Humankind has benefited from fermentation products, but from the yeast's point of view, alcohol and carbon dioxide are just waste products.

While cask ale, which undergoes a secondary fermentation in the barrel ... adding the product could instead mislead consumers and actually remove cask beer from pubs in favour of Fresh Ale. Previously ...