Cask ale

Cask ale or cask-conditioned beer is unfiltered and unpasteurised beer which is conditioned (including secondary fermentation) and served from a cask without additional nitrogen or carbon dioxide pressure. Cask ale is also sometimes referred to as real ale in the United Kingdom, a term coined by the Campaign for Real Ale, often now extended to cover bottle-conditioned beer as well.

The history of cask and keg beer

Cask means container. The Histories of Herodotus, written in 424 BC, refers to "casks of palm-wood filled with wine" being moved by boat to Babylon, though clay vessels would also have been used. Stout wooden barrels held together with an iron hoop were developed by the north European Celts during the Iron Age for storing goods. Over the centuries other methods have been developed for preserving and storing beer but this method is still used, particularly in Britain.