A barrel or cask is a hollow cylindrical container with a bulging center, longer than it is wide. They are traditionally made of wooden staves and bound by wooden or metal hoops. The word vat is often used for large containers for liquids, usually alcoholic beverages; a small barrel or cask is known as a keg.
Traditional oak barrels made by Chilean cooperage TonelerĂa Nacional
Modern stainless steel casks and kegs outside the Castle Rock microbrewery in Nottingham, England
Wooden wine barrel at an exhibition in Croatia
Pyramidal pile of herring barrels in Scheveningen, the Netherlands, c. 1940
A keg is a small cask.
50 litre DIN keg, cutaway.
Mini keg of Grolsch beer.
Example of bag-in-ball technology
88-pint beer kegs lined up outside a pub in Portlaoise, Ireland