Barrel

Traditional wooden barrels in Cutchogue, USA

Modern stainless steel beer barrels—also called casks or kegs—outside the Castle Rock microbrewery in Nottingham, England

A barrel or cask is a hollow cylindrical container, traditionally made of vertical wooden staves and bound by wooden or metal hoops. Traditionally, the barrel was a standard size of measure referring to a set capacity or weight of a given commodity. For example, a beer barrel was originally a 36 gallon capacity while an ale barrel was a 32 gallon capacity. Wine was shipped in 31.5 gallon barrels. Barrels are one size of cask. Other cask sizes include, but are not limited to, pins, firkins, kilderkins, puncheons, rundlets, tierces, pipes, butts, and tuns. Someone who makes barrels is a cooper. Modern barrels are also made of aluminium, stainless steel, and plastic.

Barrels have a variety of uses, including storage of liquids such as water and oil, fermenting wine and sake, and maturing beverages such as brandy, sherry, port, whiskey and beer.

History

In Asia/Europe in ancient times 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. Pliny the Elder in the 1st century described how barrels were used to mature wine by producers in the Alps.

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.

Starting in the late 19th century, barrels were largely superseded by corrugated fiberboard boxes for storage and transport of dry goods, and in the mid 20th century, steel drums began to be used for the storage and transport of fluids such as water, oils and hazardous waste. Barrels are still used today for artistic presentation of merchandise in many stores, although these barrels are often merely decorative, and not made water-tight.

Water storage

Water barrels are often used to collect the rainwater from dwellings (so that it may be used for irrigation or other purposes). This usage, known as rainwater harvesting, requires (besides a large rainwater barrel), an adequate (water-proof) roof-covering and an adequate rain pipe.

Oil storage

Standard Oil Company blue 55-US gallon (46 imp. gal, 208 L) barrel (drum)

The standard barrel of crude oil or other petroleum product (abbreviated bbl) is 42 US gallons (34.9723 imp gal; 158.9873 L). This measurement originated in the early Pennsylvania oil fields, and permitted both British and American merchants to refer to the same unit, based on the old English wine measure, the tierce.

Earlier, another size of whiskey barrel was the most common size; this was the 40 US gallons (33.3 imp gal; 151.4 L) barrel for proof spirits, which was of the same volume as 5 US bushels. However, by 1866 the oil barrel was standardized at 42 US gallons.

Oil has not actually been shipped in barrels ^[1] since the introduction of oil tankers, but the 42-US-gallon size is still used as a unit for measurement, pricing, and in tax and regulatory codes. Each barrel is refined into about 19.74 US gallons (16.44 imp gal; 74.7 L) of gasoline^[2], the rest becoming other products such as jet fuel and heating oil, using fractional distillation.^[3]

The current standard volume for barrels for chemicals and food is 55 US gallons (46 imp gal; 208 L).

Beverage maturing

Wine barrels in Napa Valley, California.

Whiskey barrels at the Jack Daniel's distillery

Some wine is fermented "in barrel," as opposed to a neutral container such as a steel or concrete tank. Wine can also be fermented in large wooden tanks, often called "open-tops" because they are open to the atmosphere. Other wooden cooperage for storing wine or spirits are called "casks", and they are large (up to thousands of gallons) with either elliptical or round heads.

An "aging barrel" is used to age wine, distilled spirits such as whiskey, brandy, or rum, or Tabasco sauce. When a wine or whiskey/whisky ages in a barrel, small amounts of oxygen are introduced as the barrel lets some air in (compare to microoxygenation where oxygen is deliberately added). Oxygen enters a barrel when water or alcohol is lost due to evaporation, a portion known as the "angels' share". In an environment with 100% relative humidity, very little water evaporates and so most of the loss is alcohol, a useful trick if one has a wine with very high proof. Most wines are topped up from other barrels to prevent significant oxidation, although others such as vin jaune are not.

Wine aged in small new oak barrels (Barrique) takes on some of the compounds in the barrel, such as vanillin and wood tannins. The presence of these compounds is dependent on many factors, including the place of origin, how the staves were cut and dried, and degree of "toast" applied during manufacture. After roughly three years, most of a barrel's flavor compounds have been leached out and it is well on its way to becoming "neutral."

The tastes yielded by French and American species of oak are slightly different, with French oak being subtler, while American oak gives stronger aromas.^[4] To retain the desired measure of oak influence, a winery will replace a certain percentage of its barrels every year, although this can vary from 5 to 100%. Some winemakers use 200% new oak, where the wine is put into new oak barrels twice during the aging process. Bulk wines are sometimes flavored by soaking oak chips in them instead of barrel aging.

Barrels used for aging are typically made of oak, but chestnut and redwood are also used. Some Asian traditions (e.g. Japanese sake) have been known to use Japanese cedar, which imparts an unusual, minty/piney flavor. And in Latin America, "Pisco" is aged in earthenware: minerals from the fired clay leach into the liquor giving it a unique flavor.

Beers are sometimes aged in barrels which were previously used for maturing spirits.

Angels' share

"Angels' share" is a term for the portion (share) of a wine or distilled spirit's volume that is lost to evaporation during aging in oak barrels. The barrels are typically French or American oak. In low humidity conditions, the loss to evaporation may be primarily water. However, in higher humidities, more alcohol than water will evaporate, therefore reducing the alcoholic strength of the product. In humid climates, this loss of ethanol is associated with the growth of a darkly colored fungus, Baudoinia compniacensis, on the exterior surfaces of buildings, trees and other vegetation, and anything else that happens to be nearby.^[5]

Other uses

Due to the traditional barrel's distinctive shape and construction method, the term has been used to describe a variety of other related or similar objects, such as the gun barrel (with the term growing out of the fact that early cannon were built from staves of metal hooped together, similar to a barrel)^[6] and barrel organ.

The English idiom over a barrel means to be in a predicament or helpless in a situation where others are in control: "I have no choice in the matter — my creditors have me over a barrel." The phrase is said to originate from two 19th century practices: rolling drowning victims over a barrel to clear their lungs of water, or flogging someone who is bent over a barrel.

Some kinds of food, such as pork, were stored in barrels in larders before the era of refrigerators. This practice generated a political term, pork barrel, in which earmarks for particular people or locations were labeled "pork-barrel" spending.

Shape

Barrels often have a convex shape, bulging at the middle. This constant bulge makes it easier to roll a well-built wooden 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.

Casks used for ale or beer have shives and keystones in their openings. Before serving the beer a spile is hammered into the shive and a tap into the keystone.

The "chine hoop" is the iron hoop nearest the end of a wooden barrel, the "bilge hoops" those nearest the bulge, or centre.

The stopper used to seal the hole in a barrel is called the bung.

Sizes

A barrel is one of several units of volume, with dry barrels, fluid barrels (UK beer barrel, U.S. beer barrel), oil barrel, etc. The volume of some barrel units is double others, with various volumes in the range of about 100–200 litres (22–44 imp gal; 26–53 USgal).

English wine casks

Pre-1824 definitions continued to be used in the US, the wine gallon of 231 cubic inches being the standard gallon for liquids (the corn gallon of 268.8 cubic inches for solids). In Britain the wine gallon was replaced by the Imperial gallon. The tierce later became the petrol barrel. The tun was originally 256 gallons, which explains where the quarter, 8 bushels or 64 (wine) gallons, comes from.

Brewery casks

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

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

The modern US beer barrel is 31 US gallons (116.34777 litres), half a gallon less than the traditional wine barrel. (26 U.S.C. §5051 [2])

See also

• 55 gallon drum
• Drum (container)
• Kegs
• Cask ale
• gun barrel
• Wine barrels

References

External links

• Online barrel conversions
• Origin of "over a barrel"
• Oil measurements and conversions
•  This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed (1911). Encyclopædia Britannica (Eleventh ed.). Cambridge University Press.