Cask beer is a type of beer that is conditioned and served from a cask, which is a barrel-like container. Unlike most beers that are carbonated with gas, cask beer undergoes natural carbonation through fermentation in the cask itself. This process gives it a unique flavor and a smoother texture, often enjoyed at cellar temperature. Cask beer is typically served using a hand pump or gravity, allowing for a more traditional and authentic experience. It is popular in many pubs, especially in the UK, where it is often associated with the Campaign for Real Ale (CAMRA), an organization that promotes traditional brewing methods.