Keg

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A 15.5 US gallon Keg, cutaway

A keg is a metal container (usually constructed of stainless steel) used to hold beer and other alcoholic or non-alcoholic drinks, carbonated or not carbonated, generally under pressure. Kegs are characterized by a single (mostly two way) valve in the middle of the top which is used for cleaning, filling and tapping.

(Note: A figal mostly used for soft drinks with two valves on the top is not considered to be a keg in spite of being known as a cornelius keg.)

Formerly a keg was a small barrel made by a cooper used to transport items such as nails.

1 Metrology
2 UK Keg Supply Structure
3 Tapping a keg
4 Homebrewing kegs
5 Keg laws
6 Games involving Kegs
7 Keg Hiring
8 References

[edit] Metrology

A keg is also a standard unit of measure, named for the container described above. A full keg is a 15.5 US gallon barrel, routinely called a half-barrel; a half-keg is called a quarter-barrel and has a volume of 7.75 US gallons.

A 15.5 US gallon keg is equal to:

12.5 Imperial gallons (UK)
58.67 litres
100 Imperial pints (UK)
120 US pints
164 12 oz drinks

However, beer kegs can come in many sizes:

Size (US gal)	Size (litres)	No. of 12 oz drinks	No. of 16 oz drinks	No. of 20 oz drinks	Weight of full keg (lbs)	Also known as
5	18.9	53	40	32	55-60	Home Brew / Corny Keg
5.23	19.8	56	42	33	-	Sixth Barrel
7.75	29.3	82	62	49	90	Quarter Barrel / Pony Keg
13.2	50	140	105	84	-	-
15.5	58.7	164	124	99	140 - 170	Half Barrel / Full Keg

See also barrel, firkin, kegger, pony keg.

[edit] UK Keg Supply Structure

The beer vessel supply structure in the UK 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. The kegs themselves are either steel or increasingly the more lightweight aluminium variety. The standard keg size is 11 imperial gallon (50Litre/88 imperial pints approx) and the vast majority of beers are supplied in this keg size there are also smaller 30Litre (54 imperial pints approx) kegs usually reserved for more specialist and or premium European beers.

A number of manufacturers also produce 22 imperial gallon (100Litre/172 imperial pints approx) kegs, however due to their size they are not very popular as manual handling is extremely difficult and as a result tend to be used for large scale events and bars with high throughput. The rare exception to the standard sizes is the Stella Artois beer which is the only beer in the UK (to the authors knowledge) which utilises a 10 imperial gallon (45Litre approx/80 imperial pints approx)keg.

A further keg type exists within the UK beer industry, which is a 9 imperial gallon (72 imperial pints approx) firkin for cask ales. Whilst not strictly a keg in terms of being a pressurised vessel the basic function as a recepticle for containing beer and out of which beer is dispenses is the same. The cask contains beer in a live form, in that the beer is still respiring up until the point of consumption and is not pasturised like 'keg' beers, therefore the cask is also part of the brewing and maturation process.

[edit] Tapping a keg

There are two different types of tapping equipment that are available for kegs, party pumps and gas taps. Party pumps utilize outside air, which introduce bacteria inside the keg, reducing the quality of the beer. Kegs operating a party pump should be used within 8-12 hours otherwise the beer will become undrinkable. Gas pumps normally use CO2, but certain brewers require a mix of other gases (Guinness requires 25% CO2 and 75% Nitrogen) Gas pumps can preserve a keg up to 120 days with proper refrigeration.

As with any pressurized container, a keg can cause injury, even at normal operating pressure, whether with compressed air or carbon dioxide:

"The tapping system and pressure regulator both should be equipped with a pressure relief (blow off) device. If you are not familiar with tapping equipment, consult your retailer..." (printed on an Anheuser-Busch's keg cap)

[edit] Homebrewing kegs

Homebrewers often use kegs for aging, filtering, and storing beer. These are seldom the standard kegs used by major brewers to transport draught beer to wholesalers, but instead are reconditioned Cornelius kegs (colloquially known as 'cornies,') many of which formerly contained soda.

These kegs are stainless steel cylinders that hold approximately 5 gallons of liquid. The keg is filled with liquid (wort or beer) via a removable hatch on the top, which is then closed and sealed. Carbon dioxide is added to presurize the keg via an inlet port on the top and is facilitated by gently rocking the brew back and forth. Liquid is dispensed via an outlet port attached to a tube that extends to the bottom of the keg. Pin-lock and ball-lock fittings (or posts) are the two types of couplings used on the inlet and outlet ports. Older kegs tend to use pin-lock fittings, while newer kegs tend to use ball-lock fittings, though the fittings themselves are removable, serviceable, and interchangeable parts.

[edit] Keg laws

Main article: Keg registration

In the U.S. as of 2005, there are 21 states and numerous localities that have keg registration laws. The laws vary widely in terms of whom they target, what their intended purpose is, and how strongly they are enforced.

[edit] Games involving Kegs

There are many games that involve kegs, including keg races, keg riding and keg tossing. Keg games may or may not involve drinking as an integral part of the competition; games in which the keg is carried or thrown obviously require the use of an empty keg.

"Keg Races" may refer to a competition in which the participants must spin around a keg a number of times, and usually consume some amount of beer, or the keg may have to be carried as an extra large "baton" in an athletic race. Another variant Keg Race, (known as "Continuous Keg" in Australia) involves large teams who attempt to drink an entire keg without ever turning off the tap. The University of Florida has its own variant of the Keg Race. It involves purchasing two kegs and assembling a decent sized group of people. The group is divided and each is assigned to a keg. The team which finishes their keg first wins. But Joakim Noah is not allowed to participate in fear of mono or ugliness being spread. And Greg Paulus still isn't enough of a "big boy" to drink alcohol.

In America, kegs have become synonymous with college parties, which are sometimes called "keggers". These parties, however, typically only utilize the beer inside the keg for games such as beer pong and flip cup, and do not use the empty barrel in a competitive way.

Another game popular in America is the "keg stand", in which people are held upside down with the tap in their mouth, and try to consume beer for as long as possible.

[edit] Keg Hiring

Keg hiring is the act typically of obtaining a keg for the purposes of consumption at an event or party.

In the US and Australia the typical application of the keg hire is by using either a keg stored in a bucket of ice/water and/or the beer is passed through a beer line coil in ice to cool the beer. The beer is then usually dispensed directly from the keg via an attached tap where the beer is cooled by the bucket method, the latter method is usually dispensed by a tap on the side of an insulated cool box (which contains ice and the coil). The keg in this scenario is typically manually pumped using air (picnic pumps as described above) to pressurise the keg thereby maintaining carbonation and providing enough force to expell the beer from the keg. The kegs are not usually gas dispensed however for more permanent setups such as home bars this is more common due to freshness issues. Example firms from the US and Australia respectively for more up-to-date information: Mr Kegs Amazing Wheelie Keg

In the UK the keg hiring scene is significantly less well developed and is in its infancy, this is likely to be from a number of factors such as the relatively poor weather in contrast to the US and Australia making outdoor oriented parties less popular, also due to the restrictive nature of the industry supply structure and the pronounced UK 'pub' culture. A notable difference in the UK market however is the method of dispense which focuses of cooling the beer primarily after it leave the keg. Whilst the US and Australia tend to have high ambient temperatures, keeping the keg itself cold is essential, to ensure the carbon doixide in the beer does not seperate and therefore cause the beer to fob (go frothy), the UK however doesn't usually have the same problem as temperatures are usually much lower. By cooling outside the keg and the limited supply of ice commonly available it is common to use under bar 'flash' coolers, these operate on the same basic principle as the cool box and the coil however are electrically powered and cool a bath of water into an ice block around the coil. This provides an very tidy and effective method for dispensing cold beer. An example of a UK keg hire firm: Kegless Keg Hire