Capacities of brewery casks were formerly measured and standardised according to a specific system of English units. The system was originally based on the ale gallon of 282 cubic inches (4.62 L; 1.22 US gal). In United Kingdom and its colonies, with the adoption of the imperial system in 1824, the units were redefined in terms of the slightly smaller imperial gallon (1.2 US gal; 4.5 L). The older units continued in use in the United States.
Historically the terms beer and ale referred to distinct brews.[nb 1] From the mid 15th century until 1803 in Britain "ale" casks and "beer" casks differed in the number of gallons they contained.
The tun is a cask that is double the size of a butt and is equal to eight barrels and has a capacity of 252 imperial gallons (303 US gal; 1,150 L). Invented in Brentford, a tun was used in local breweries to measure large amounts of alcohol.
/* originally 256 but 252 by 1347 barrels in 1454 were 32 gallons (32*8=256) 1/8th the original Tun noted here to correct previous edits that said math was wrong  */
The butt of beer was equal to half a tun, two hogsheads, three barrels or 108 imperial gallons (129.7 US gal; 491.0 L).
- hogshead (Ale)
- In the mid-15th century the ale hogshead was defined as 48 ale or beer gallons (221.8 L). In 1688 the ale hogshead was redefined to be 51 ale or beer gallons (235.7 l). In 1803 the ale hogshead was again redefined to be 54 ale or beer gallons (249.5 l), equivalent to the beer hogshead.
- hogshead (Beer)
- From the mid 15th century until 1824 the beer hogshead was defined as 54 ale or beer gallons.
- hogshead (Ale) (Imperial), hogshead (Beer) (Imperial)
- In the United Kingdom and its colonies, with the 1824 adoption of the imperial system, the ale or beer hogshead was redefined to be 54 imperial gallons. The ale or beer hogshead is therefore exactly 245.48886 litres or approximately 8.669 cubic feet.[nb 2]
- barrel (Ale)
- As with the hogshead the ale barrel underwent various redefinitions. Initially 32 ale or beer gallons (147.9 L), it was redefined in 1688 as 34 ale or beer gallons (157.1 L) and again in 1803 as 36 ale or beer gallons (166.4 L).
- barrel (Beer)
- The beer barrel was defined as 36 ale or beer gallons until the adoption of the imperial system.
- barrel (Ale) (Imperial), barrel (Beer) (Imperial)
- The adoption of the imperial system saw the beer or ale barrel redefined to be 36 imperial gallons, which is exactly
- 9,987.09958 cubic inches or approximately 163.659 litres.[nb 2]
The kilderkin (from the Dutch for "small cask") is equal to half a barrel or two firkins.
- kilderkin (Ale)
- The ale kilderkin likewise underwent various redefinitions. Initially 16 ale or beer gallons (73.94 L), it was redefined in 1688 as 17 ale or beer gallons (78.56 L) and again in 1803 as 18 ale or beer gallons (83.18 L).
- kilderkin (Beer)
- Until the adoption of the imperial system the beer kilderkin was defined as 18 ale or beer gallons.
- kilderkin (Ale) (Imperial), kilderkin (Beer) (Imperial)
- With the adoption of the imperial system the kilderkin was redefined to be 18 imperial gallons, which is exactly 81.82962 litres[nb 2] or approximately 2.890 cubic feet.
The kilderkin is still currently used. It is the unit of choice of CAMRA, the Campaign for Real Ale, for calculating beer quantities for beer festivals in the UK. Ales are usually delivered in firkins, cider and other drinks are usually in boxes, bottles or other containers measured in gallons or litres, and all (except wine) are sold in pints or parts thereof. For CAMRA internal accounting, all are calculated in kilderkins. A kilderkin is a 144 pint container but there is not 144 pints of cask conditioned consumable beer in a kilderkin (see Firkins below for explanation).
The ale or beer firkin (from Middle Dutch vierdekijn meaning "fourth") is a quarter of an ale or beer barrel or half a kilderkin. This unit is much smaller than the wine firkin. Casks in this size (themselves called firkins) are the most common container for cask ale.
- firkin (Ale)
- From the mid 15th century until 1688 the ale firkin was defined as 8 ale or beer gallons (36.97 litres). In 1688 the ale firkin was redefined to be 8+1⁄2 ale or beer gallons (39.28 L). In 1803 ale firkin was again redefined to be 9 ale or beer gallons (41.59 L), equivalent to the beer firkin.
- firkin (Beer)
- From the mid 15th century until 1824 the beer firkin was defined as 9 ale or beer gallons.
- firkin (Ale) (Imperial), firkin (Beer) (Imperial)
- The beer or ale firkin was redefined to be 9 imperial gallons in 1824. It is therefore exactly 40.91481 litres[nb 2] or approximately 1.445 cubic feet.
Most English cask conditioned beer bought by publicans is delivered in 72 pint containers (i.e. Firkin) but the volume of consumable beer in the container is far lower. For example a 72 pint container of Greene King IPA currently only has 66 "full" pints of consumable beer that can be sold or drunk, the other 6 pints are sediment, finings, beer stone, hops, proteins or less than a imperial measure and therefore not consumable or saleable. HMRC does not charge duty on any portion of beer that cannot be consumed, brewers should make a declaration to the first customer (i.e. publican) to inform them what are the actual duty paid contents of the beer so customers are fully aware of how much is being sold to them.
A pin is equal to half a firkin (4.5 imp gal or 20 L). Plastic versions of these casks are known as "polypins" and are popular in homebrewing and the off-trade (deliveries for home consumption). They are also popular at beer festivals where non-standard beers are sold.
|= 4.621 L||= 36.97 L||= 73.94 L||= 147.9 L||= 221.8 L|
|= 4.621 L||= 41.59 L||= 83.18 L||= 166.4 L||= 249.5 L|
|= 4.621 L||= 39.28 L||= 78.56 L||= 157.1 L||= 235.7 L|
|= 4.621 L||= 41.59 L||= 83.18 L||= 166.4 L||= 249.5 L|
|= 4.546 L||= 40.91 L||= 81.83 L||= 163.7 L||= 245.5 L|
- Oxford English Dictionary Online
- "English Beer and Ale Barrel".
- "BEER3430 - Beer Guidance - HMRC internal manual - GOV.UK".
- "English Beer and Ale Barrel". Sizes. 2002-01-23. Retrieved 2018-03-27.
- The term beer was reserved for beer brewed with hops whilst ale referred to beer brewed without hops.
- This assumes the current 4.54609-litre definition of the imperial gallon.