Barrel
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.
Barrels have a variety of uses, including storage of liquids such as water, oil, and alcohol. They are also employed to hold maturing beverages such as wine, cognac, armagnac, sherry, port, whiskey, beer, arrack, and sake. Other commodities once stored in wooden casks include gunpowder, meat, fish, paint, honey, nails, and tallow.
Modern wooden barrels for wine-making are made of English oak, white oak, American white oak, more exotic is mizunara oak, and recently Oregon oak has been used.
Someone who makes traditional wooden barrels is called a cooper. Today, barrels and casks can also be made of aluminum, stainless steel, and different types of plastic, such as HDPE.
Early casks were bound with wooden hoops and in the 19th century these were gradually replaced by metal hoops that were stronger, more durable and took up less space.
Barrel has also been used as a standard size of measure, referring to a set capacity or weight of a given commodity. For example, in the UK and Ireland, a barrel of beer refers to a quantity of, and is distinguished from other unit measurements, such as firkins, hogsheads, and kilderkins. Wine was shipped in barrels of. A barrel of oil, defined as, is still used as a measure of volume for oil, although oil is no longer shipped in barrels. The barrel has also come into use as a generic term for a wooden cask of any size.
History
An Egyptian wall-painting in the tomb of Hesy-Ra, dating to 2600 BC, shows a wooden tub used to measure wheat and constructed of staves bound together with wooden hoops. Another Egyptian tomb painting dating to 1900 BC shows a cooper and tubs made of staves in use at the grape harvest. Herodotus allegedly reports the use of "palm-wood casks" in ancient Babylon, but some modern scholarship disputes this interpretation.In Europe, buckets and casks dating to 200 BC have been found preserved in the mud of lake villages. A lake village near Glastonbury dating to the late Iron Age has yielded one complete tub and a number of wooden staves.
The Roman historian Pliny the Elder reported that cooperage in Europe originated with the Gauls in Alpine villages who stored their beverages in wooden casks bound with hoops. Pliny identified three different types of coopers: ordinary coopers, wine coopers and coopers who made large casks. Large casks contain more and bigger staves and are correspondingly more difficult to assemble. Roman coopers tended to be independent tradesmen, passing their skills on to their sons. The Greek geographer Strabo recorded that wooden pithoi were lined with pitch to stop leakage and preserve the wine.
Barrels were sometimes used for military purposes. Julius Caesar used catapults to hurl burning barrels of tar into besieged towns to start fires. The Romans also used empty barrels to make pontoon bridges to cross rivers.
Empty casks were used to line the walls of shallow wells from at least Roman times. Such casks were found in 1897 during archaeological excavations of Roman Silchester in Britain. They were made of Pyrenean silver fir and the staves were thick and featured grooves where the heads fitted. They had Roman numerals scratched on the surface of each stave to help with re-assembly.
In Anglo-Saxon Britain, wooden barrels were used to store ale, butter, honey and mead. Drinking-containers were also made from small staves of oak, yew or pine. These items required considerable craftsmanship to hold liquids and might be bound with finely-worked precious metals. They were highly valued items and were sometimes buried with the dead as grave goods.
In medieval and early modern Northern Europe, wooden casks were the primary container for wet and dry cargoes carried by ships, akin to the ceramic amphora transport jars used from antiquity in the Mediterranean region. Wooden barrels carried foodstuffs such as fish, beer, honey, butter, apples, raisins, nuts, malt, beans, peas, grain, barley, and oats. Gunpowder, iron, tar, coals, potash, lime, vinegar, and candles were transported in barrels; and no doubt much more. As with amphoras, different production centers applied various volumetric standards to the casks. This was enforced in some places by using sophisticated methods of gauging the casks, and then certifying the standard by municipal seals. In other places, such as the Hanseatic League town of Rostock, barrel volume was determined by the number of dressed and salted herring packed into them. Some Hanse traders enforced their standards by destroying casks that did not conform. Standardized cask volume was therefore an indicator of political economy.
Uses today
Beverage maturing
An "ageing barrel" is used to age wine; distilled spirits such as whiskey, brandy, or rum; beer; tabasco sauce; or traditional balsamic vinegar. When a wine or spirit ages in a barrel, small amounts of oxygen are introduced as the barrel lets some air in. 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 beverages are topped up from other barrels to prevent significant oxidation, although others such as vin jaune and sherry are not.Beverages aged in wooden barrels take on some of the compounds in the barrel, such as vanillin and wood tannins. The presence of these compounds depends on many factors, including the place of origin, how the staves were cut and dried, and the degree of "toast" applied during manufacture. Barrels used for aging are typically made of French or American oak, but chestnut and redwood are also used. Some Asian beverages use Japanese cedar, which imparts an unusual, minty-piney flavor. In Peru and Chile, a grape distillate named pisco is either aged in oak or in earthenware.
Wines
Some wines are fermented "on barrel", as opposed to in a neutral container like steel or wine-grade HDPE tanks. Wine can also be fermented in large wooden tanks, which—when open to the atmosphere—are called "open-tops". Other wooden cooperage for storing wine or spirits range from smaller barriques to huge casks, with either elliptical or round heads.The tastes yielded by French and American species of oak are slightly different, with French oak being subtler, while American oak gives stronger aromas. 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 more cheaply flavored by soaking in oak chips or added commercial oak flavoring instead of being aged in a barrel because of the much lower cost.
Sherry
is stored in casks made of North American oak, which is slightly more porous than French or Spanish oak. The casks, or butts, are filled five-sixths full, leaving "the space of two fists" empty at the top to allow flor to develop on top of the wine. Sherry is also commonly swapped between barrels of different ages, a process that is known as solera.Spirits
Whiskey
Laws in several jurisdictions require that whiskey be aged in wooden barrels. The law in the United States requires that "straight whiskey" must be stored for at least two years in new, charred oak containers. Other forms of whiskey aged in used barrels cannot be called "straight".International laws require any whisky bearing the label "Scotch" to be distilled and matured in Scotland for a minimum of three years and one day in oak casks.
By Canadian law, Canadian whiskies must "be aged in small wood for not less than three years", and "small wood" is defined as a wood barrel not exceeding capacity.
Since US law requires the use of new barrels for several popular types of whiskey, which is not typically considered necessary elsewhere, whiskey made elsewhere is usually aged in used barrels that previously contained American whiskey. The typical bourbon barrel is in size, which is thus the de facto standard whiskey barrel size worldwide. Some distillers transfer their whiskey into different barrels to "finish" or add qualities to the final product. These finishing barrels frequently aged a different spirit or wine. Other distillers, particularly those producing Scotch, often disassemble five used bourbon barrels and reassemble them into four casks with different barrel ends for aging Scotch, creating a type of cask referred to as a hogshead.