A barrel is a hollow cylindrical container, traditionally made of wood staves and bound with iron bands. Someone who makes such barrels is known as a cooper. Contemporary barrels are also made in aluminium (also called Kegs) and plastic.

Barrels often have a convex shape, bulging at the middle. This constant bulge makes it relatively easy to roll a well built wooden a barrel on its side, changing directions with little friction. It also helps to distribute stress evenly in the material by making the container more spherical.

History

In ancient times, in Europe, liquids like oil and wine were carried in vessels, for instance amphora, sealed with pine resin. The Romans began to use barrels in the 3rd century AD, as a result of their commercial and military contacts with the Gauls, who had been making barrels for several centuries.

For nearly 2,000 years barrels were the most convenient form of shipping or storage container, for those who could afford the superior price. All kinds of bulk goods, from nails to gold coins, were stored in them. Bags and most crates were cheaper, but they were not as sturdy and they were more difficult to manhandle, for the same weight. Barrels slowly lost their importance in the 20th century, with the introduction of pallet based logistics and Containerization.

Aging in barrels

Main article: Aging barrel

Barrels are used for the storage of liquids, to ferment wine, and to age wine (notably brandy, sherry, and port) and whiskey. Some wine is said to be fermented "in barrel," as opposed to a neutral container such as a steel or concrete tank. The barrels used for this can be hundreds or even thousands of gallons.

Beer "Barrels"

Although it is common to refer to draught beer containers of any size as barrels, this is strictly correct only if the container actually holds 36 gallons. The terms "keg" and "cask" refer to containers of any size, the distinction being that kegs are used for pasteurised beers intended to be served using external gas cylinders. Real ale and similar beers undergo part of their fermentation process in their containers, which are called casks.

Casks are available in several sizes, and it is also usual to refer to "a firkin" or "a kil" (kilderkin) instead of a cask.

Sizes

English traditional, wine

Like other units, the pre-1824 definitions continued to be used in the US, the wine gallon of 231 cubic inches staying (since 1707) the standard gallon for liquids (accompanied by the corn gallon of 268.8 cubic inches for solids), whereas in Britain that gallon was abolished and replaced by the Imperial gallon. The tierce later became the petrol barrel. The tun originally was 256 gallons, which explains where the quarter, being 8 bushels or 64 (wine) gallons, comes from.

English traditional, beer and ale