Keg
[2] Nowadays a keg is normally constructed of stainless steel, although aluminium can be used if it is coated with plastic on the inside.
This includes the UK, which uses a non-metric standard keg of 11 imperial gallons, which is, by coincidence, equal to 50.007 litres.
[citation needed] Kegs are sealed to contain the liquid and pressurized gas for storage and transportation.
To serve the beverage, a keg must be tapped to breach the container so that pressurized gas can be added and the liquid can be dispensed.
By the 1950s and 60s when metal kegs had replaced wooden ones, common tap systems included Golden Gate, Hoff–Stevens, and Peerless taps, which all had one or two couplers for pressurizing and dispensing the beer but retained a separate bunghole for cleaning and filling the keg which was sealed with a wooden bung.
In the 1960s and 70s, several similar styles of tap were created in Europe and America which used a single hole for cleaning, filling, pressurizing, and dispensing.
[13] The term Sankey, often misspelled "Sanke", has become a generic name for all of the similar industry standard couplers.
Today there are six industry standard couplers:[14] There are two different types of tapping equipment that are available for kegs.
Commercial installations, as well as some home users, use pure pressurized gas; these can preserve a keg up to 120 days with proper refrigeration.
Nitrogen is 80 times less soluble in water than CO2, so it can provide additional pressure without noticeably affecting flavor.
Alternately, the keg can be kept at ambient temperature and served using a "jockey box", consisting of a cooler with beer coils (50–120-foot-long (20–40 m) metal dispensing lines arranged in a coil) and filled with ice, which acts as a heat exchanger to cool the beer to serving temperature by the time it reaches the faucet.
European consumers, when not using a party pump, mainly use inline beer chillers, essentially the same concept as a jockey box but using a refrigeration unit instead of ice.
Since the arrival of newer technology such as bag-in-box packages, Cornelius kegs have become largely obsolete in the soft drink industry, and refurbished ones are readily available to hobbyists.
This name has now been genericized to generally apply to all 5-liter mini kegs in Canada [citation needed].
Today, mini kegs are widely available in liquor stores worldwide, with Heineken, Grolsch and Bitburger all adopting the design.
Some types have a cardboard outer packaging, which makes them easier to stack and transport, and also protects the plastic container.
A quarter barrel, more commonly known as pony keg, is a beer vessel containing approximately 7.75 U.S. gallons (29.33 liters) of fluid.
However, it shares many inconveniences with the bigger kegs, such as: often requiring a deposit when purchased, needing a tap to serve the contents, and posing difficulties in determining the amount of beer remaining (weighing the keg or observing its buoyancy are common techniques).
In some places, such as Cincinnati, the term pony keg can mean a convenience store that sells beer.
Other than smaller circumference, sixth barrel kegs are very similar to their full-sized counterparts in construction.
[citation needed] The beer vessel supply structure in the UK and Ireland is quite different, whilst the couplers for kegs have been largely standardised to sankey, grundy and interbrew, a couple of others exist such as UEC and U-Type, however these are much less common.
There are also smaller 30 litre (≈52.7926 imperial pints) kegs usually reserved for more specialist and premium European beers.
