Cask

A barrel-shaped container used for the production, storage, and service of cask-conditioned beer, known as real ale in the UK.

While casks were traditionally made of wood, most casks today are made of stainless steel. 

There are several types of cask sizes with different names and volumes that are multiples of each other:

• Pin - 5.4 US gallons
• Firkin - 10.8 US gallons
• Kilderkin - 21.6 US gallons
• Barrel - 43.2 US gallons
• Hogshead - 64.8 US gallons