Keg
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 | This article may require copy editing for grammar, style, cohesion, tone, or spelling. (March 2007) |
A keg is a cylindrical container, usually constructed of aluminum, steel or wood. A keg is commonly used to store, transport, and serve beer. Other alcoholic or non-alcoholic drinks, carbonated or non-carbonated, may be housed in a keg as well. These liquids are generally under pressure.
Formerly a keg was a small barrel made by a cooper used to transport items such as nails[citation needed].
Metrology
Since keg sizes are standardized, the keg can be used as a standard unit of measure for liquid volumes.
A full keg is a 15.5 U.S. gallon barrel, routinely called a half-barrel. A half keg or pony keg is therefore called a quarter-barrel and has a volume of 7.75 U.S. gallons. Generally a keg is a vessel smaller than a barrel, thus it is 30 gallons or smaller.[1]
The terms half-barrel and quarter-barrel are derived from the fact that a U.S. beer barrel is legally defined as being equal to 31 U.S. gallons (note that this is not the same volume as some other units commonly known as barrels. A 15.5 U.S. gallon keg is also equal to:
- 12.9 Imperial gallons
- 58.67 liters
- 103.25 Imperial pints
- 124 U.S. pints
- 165 12 fluid ounce drinks
- About 6.88 24-unit cases of 12 oz. cans.
- 1984 ounces
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 | - | Import Keg |
| 15.5 | 58.7 | 165 | 124 | 99 | 140 - 170 | Half Barrel / Full Keg |
Differences between a keg and a cask
In brewing parlance, a keg is different from a cask. The keg is built with a downtube located in its center with a valve to force gasses out when filling and air in when dispensing. Kegs are artificially pressurised after fermentation with carbon dioxide or a mixture of carbon dioxide and nitrogen gas. A cask has a tap hole near the edge of the top, and a spile hole on the side used for conditioning the unfiltered and unpasteurised beer. Casks are simply gravity-fed for the dispensing of liquids. Additionally, kegs have a simple concave bottom whereas a cask is flat on the bottom. The concavity allows for sediment to be captured away from the flow pipe in the keg. Lastly, kegs have straight sides, unlike the traditional barrel or cask shape.
Keg Beer
Keg beer is a term for beer which is served from a pressurized keg. While often considered synonymous to draught beer, keg beer refers specifically to beer served under pressure, while draught beer may refer to any beer served from a larger container, including both keg beer and cask ale. Keg beer is often filtered and/or pasteurized, both of which are processes that render the yeast inactive, increasing the shelf life of the product at the expense of flavor.
Keg has become a term of contempt used by some since the 1960s as pasteurised draught beers were replacing traditional cask beers. The quality of the kegging process was not as good then as it is today, and sometimes the keg beers are referred to as Plastic Beer. Some people believed that chemicals (adjuncts) were used to create a foam head. These perceptions still mar keg beer to this day.
Despite this consumer concern, keg beer was replacing traditional cask ale in all parts of the UK, primarily because it requires less care to handle. Since the mid-1970s, the Campaign for Real Ale (CAMRA) has been conducting a successful consumer campaign which focused attention on those consumers who preferred traditional cask beer. As well as this, CAMRA has successfully lobbied the British Parliament to ensure support for cask ale. New, small microbreweries have sprung up to serve those consumers who prefer traditional cask beer. Today most pubs in the UK will serve both keg and cask beer.
The Mini Keg
Many beer brands are now producing a 5-liter mini keg for retail sales. Some brands come with a spout and pour from the bottom via gravity; while others such as the Heineken DraughtKeg come pressurized, include a tap, and pour from the top.
In Canada, Molson Canadian dubbed the mini keg Bubba (see photo). Much like other brand names (see genericized trademark), the name is now generally applied to all 5-liter mini kegs in Canada. This might cause confusion, as a company called Bubba Keg[1] is established in the U.S., and appears to not be associated with Molson.
The Pony Keg
A pony keg is a beer vessel containing 7.75 U.S. gallons (29.33 liters) of fluid. It is half the size of the standard beer keg and equivalent to a quarter of a barrel. It will serve roughly 82 twelve ounce cups. The shape of a pony keg resembles that of a full-sized keg, while being much easier to move manually. 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). Despite this, a pony keg can be a cheap way to provide beer for a medium-sized party.
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 aluminum variety. The standard keg size is 11 imperial gallons (50 liter/88 imperial pints approx) and the vast majority of keg beers are supplied in this keg size. There are also smaller 30 liter (54 imperial pints approx) kegs usually reserved for more specialist and or premium European beers.
A number of manufacturers also produce 18 imperial gallon (approximately 82 litres/144 imperial pints) and 22 imperial gallon (approximately 100 litres/172 imperial pints) kegs, however owing to their size they are not so popular as manual handling is seen by some to be difficult, and as a result they tend to be used only for large scale events and bars with high throughput.
For bars that sell an excessive volume of beer there is the 33 imperial gallon (150Litre/260 imperial pints approx) keg, however due to its very large size few people can move them making it an impratical choice.
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 may introduce bacteria inside the keg, reducing the quality of the beer. Kegs operating a party pump should be used within 18-24 hours otherwise the beer will become unpalatable. 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)
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") that were originally manufactured to store soda - these vessels are much easier to fill, clean and maintain than standard beer kegs.
These kegs are stainless steel cylinders that hold approximately 5 U.S. 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 pressurize 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. Coke distrubutors used pin-lock fittings, while Pepsi distributors used ball-lock fittings. Ball-lock are most used. The pin-lock style is often referred to as a "Coke" keg or style and the ball-lock is often referred to as a "Pepsi" keg or style, though the fittings themselves are removable, serviceable, and contain interchangeable parts.[2]
Homebrewers often use 15.5 U.S. gallon kegs for boiling vessels in creating wort. The kegs are drilled for a drain at the bottom, and the top cut open to create a large stainless steel cooking kettle.
Alternatively, kegs specifically designed for home brewing are available[3]. The capacity may be matched to commercial extract brewing kits - typically 12 and 23 litres. Smaller 2.5 gallon kegs[4] are also made for ease of transporting to a function.
Cleaning and Care
All kegs may have residual pressure, and this must be vented to avoid having the valve explode and injure or kill a person as the valve shoots out. Conventional 15.5 U.S. gallon kegs have circle spring clips that can be removed to release the tap valve. Some kegs such as those used by Miller have threaded valves from Micro Matic that, after venting, can be opened by lightly tapping the valve ears with a mallet or using a pry bar spun out counterclockwise. These valves then need to have the ball lock depressed while the valve head is lifted to overcome a safety. The safety prevents the valve from releasing under pressure.
It is recommended that kegs not be sterilized with bleach to avoid unpleasant residuals. Iodine based solutions or specialty cleansers such as PBW are most commonly used. The ball lock valves may be unscrewed using wrenches to allow further cleaning or replacement of O-rings or poppet valves.
Keg laws
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.
Games involving kegs
There are many games involving kegs. Some of the more popular ones include keg races, keg riding and keg tossing. Some keg games involve the consumption of the beer inside the keg itself as part of the competition, while others involve doing various things (carrying, tossing, etc) with an empty keg. For example, "Keg Race" can refer to a game in which the participants must spin around a keg a number of times, and usually consume some set amount of beer. But it can also refer to a game in which an empty keg is actually carried as an extra large "baton" in an athletic race. On college campuses, the standard version of "Keg Race" pits two teams (often rival fraternities) against each other, each with a keg, in a race to see who can finish their keg first. In another variant, (known as "Continuous Keg" in Australia), a large group of people will get together and attempt to collectively drink an entire keg without ever turning off the tap.
In America, kegs have become a staple at college parties, which are sometimes called "keggers". Popular keg games played at keggers include beer pong and flip cup. Another game popular in America is the "keg stand", in which the participant is held upside down with the tap in his or her mouth, drinking. The crowd often chants a simple phrase such as "chug! chug!" or counts off the seconds that the participant has been upside-down.
Keg hiring
Keg hiring is the act of obtaining a keg for the purposes of consumption, typically 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 or 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 expel 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.
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 dispensing which focuses on cooling the beer primarily after it leaves the keg. Because the US and Australia tend to have high ambient temperatures, keeping the keg itself cold is essential to ensure the carbon dioxide in the beer does not separate and therefore cause the beer to fob (go frothy). The UK does not usually have the same problem as temperatures are lower. A number of dispense issues and solutions for the UK-style setup can be referred to here on a UK keg hire website Kegless. By cooling outside the keg and the limited supply of ice easily 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 a very tidy and effective method for dispensing cold beer.
See also
References
- ^ keg. Merriam-Webster Online Dictionary. 2004. Retrieved 2007-06-21.
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External links
- Keg Beer Dispensing Articles and Education
- OSHA: Beverage Delivery Ergonomics
- Micromatic FAQ about Beer
- Keg FAQs Frequently asked questions on how to set up a keg of beer and how to maintain keg tapping equipment.
- Beer Brand / Keg Coupler Listing Reference Guide: Match the beer brand with the correct keg coupler (keg tap) or keg pump.