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Keg
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A keg is a cylindrical container, usually constructed of aluminum, steel or wood. It 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. Such liquids are generally kept under pressure.
Formerly a keg was a small, usually wooden barrel made by a cooper used to transport items such as nails and gunpowder.
orically a beer barrel was a standard size of 50 gallons, opposed to a wine barrel at 32 gallons, or an oil barrel at 42 gallons.
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Encyclopedia
A keg is a cylindrical container, usually constructed of aluminum, steel or wood. It 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. Such liquids are generally kept under pressure.
Formerly a keg was a small, usually wooden barrel made by a cooper used to transport items such as nails and gunpowder.
Size
Historically a beer barrel was a standard size of 50 gallons, opposed to a wine barrel at 32 gallons, or an oil barrel at 42 gallons. Over the years barrel sizes have evolved and breweries throughout the country use different sized containers. Most U.S. brewers sell beer in 1/2 barrels between 14 and 16 gallons, 1/4 barrels between 7 and 8 gallons, and 1/6 barrels between 5 and 6 gallons.
Since keg sizes are not standardized, the keg cannot be used as a standard unit of measure for liquid volumes. This size standard varies from country to country and brewery to brewery with many countries using the metric system rather than U.S. gallons.
A full keg is a 15.5 U.S. gallon barrel, routinely called a half-barrel. A Quarter Barrel 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.
In the U.S. 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:
- 12.69 Imperial gallons
- 58.67 liters
- 103.25 Imperial pints
- 124 U.S. pints
- 165 twelve fluid ounce (U.S. measure) drinks
- About 6.88 24-unit cases of 12 fl oz cans.
- About 5.5 30-racks of 12 fl oz cans.
- 1984 fluid ounces (U.S.)
However, beer kegs can come in many sizes:
| Size (US gal) | Size (litres) | No. of 12 fl oz drinks | No. of 16 fl oz drinks | No. of 20 fl oz drinks | Weight of full keg (lb) | Also known as |
|---|
| 1.32 | 5 | 14 | 10.6 | 8.5 | - | Mini Keg / Bubba (single-use/recyclable) | | 5 | 18.9 | 53 | 40 | 32 | 55-60 | Soda syrup / Corny Keg / Home Brew | | 5.23 | 19.8 | 56 | 42 | 33 | - | Sixth Barrel | | 6.6 | 25 | 70 | 50.25 | 42 | - | "Half Barrel" (Europe) | | 7.75 | 29.3 | 82 | 62 | 49 | 90 | Quarter Barrel / Pony Keg | | 13.2 | 50 | 140 | 105 | 84 | - | Import Keg (standard European "Barrel") | | 15.5 | 58.7 | 165 | 124 | 99 | 140 - 170 | Half Barrel / Full Keg |
In European countries the most common keg size is 50 liters - this includes the UK with its non-metric keg system where the standard keg of 11 imperial gallons is almost exactly the size of 50 liters in the metric system. The German DIN 6647-1 and DIN 6647-2 have also defined Kegs in the sizes of 30 and 20 liters. A newer Euro regulation defines 50, 30, 25 and 20 liters where the Keg shape is usually thicker but less tall than the German keg specifications.
| content | DIN 6647-1/-2 | Euro-Keg | Diameter |
|---|
| 50 l (13.21 gal) | 600 mm (high) | 532 mm (high) | steel keg 408 mm (Euro) / 381 mm (DIN) | | 30 l (7.93 gal) | 400 mm (high) | 365 mm (high) | steel keg 408 mm (Euro) / 381 mm (DIN) | | 25 l (6.61 gal) | - | 327 mm (high) | steel keg 395 mm (Euro) | | 20 l (7.93 gal) | 310 mm (high) | 216 mm (high) | steel keg 395 mm (Euro) / 363 mm (DIN) |
In some areas it is common to refer to the size not in liters but in beers. In areas where the standard beer size is 0.5 liters (e.g. Germany) that makes a 50 liter keg to be 100 beers.
Specifications for a U.S. 1/2 barrel keg
Accepted specifications for a standard keg are:
| Height of keg | 23.3 inches | | Diameter of keg | 16.1–17.15627 inches | | Contents | 1984.0 U.S. fluid ounces | | 15.5 U.S. gallons | | 12.91 imp. gallons | | 58.7 liters | | Full keg weight | 160.5 pounds (72.8 kg) | | Empty keg weight | 29.7 pounds (13.5 kg) | | Beer weight | 130.8 pounds (59.3 kg) | | 24×12 fl oz case equivalent | 6.9 cases | | 12 fl oz servings | 165.6 | | 16 fl oz (1 U.S. pint) servings | 124 |
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, removing all yeast from the beer, which assures a clear beer without yeast flavor, but reduces the shelf life. Pasteurization might also be employed, killing any yeast or other microorganisms in the beer which might affect its flavor over time.
Keg has become a term of contempt used by some since the 1960s as pasteurized 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.
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 many pubs in the UK will serve both keg and cask beer.
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 and will certainly introduce oxygen, which will cause the beer to oxidize, creating a wet cardboard taste, therefore reducing the quality of the beer. Kegs operating a party pump should be used within 18–24 hours otherwise the beer may 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)
Generally, in the US and Australia kegs or the beer coil are kept in a bucket of ice and/or water, in order to keep the beer cool. Keg use is somewhat different in the UK.
Other types of kegs
Mini keg
The mini keg is a 5-liter keg produced for retail sales. Some brands come with a spout and pour from the bottom via gravity, while others may use a low cost pressurized tap. Mini kegs are typically not returned to the manufacturer for cleaning and refilling. The kegs, being made of aluminum, may be recycled.
In Canada, Molson brewery dubed the mini keg "Bubba." Much like other brand names, the name is now generally applied to all 5-liter mini kegs in Canada. This might cause confusion, as a company called Bubba Keg is established in the U.S., and appears to not be associated with Molson.
Another type of mini keg is the "beer ball", a disposable plastic ball that usually holds around 5.2 gallons, roughly the equivalent of fifty five twelve-ounce beers, though they can also be found in a smaller, 3.8 gallon size. Like kegs, it is necessary to tap the ball before the beer inside it can be served.
Pony keg (Quarter Barrel)
A pony keg, more commonly known as a Quarter Barrel is a beer vessel containing approximately 7.75 U.S. gallons (29.33 liters) of fluid. The official measure of a beer barrel is 36 Gallons and a 1/4 Barrel should by definition contain 9 gallons, however, breweries in the U.S. do not use standard sizes for beer kegs. 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 (150 litre/260 imperial pint) keg, however due to its very large size few people can move them making it an impractical choice.
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 distributors 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.
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. Many times, the piece of metal cut out of the top is re-used to create a false bottom for straining wort during the mashing process, as well as to strain the boiled wort when adding hops without using a mesh grain bag.
Alternatively, kegs specifically designed for home brewing are available. The capacity may be matched to commercial extract brewing kits—typically 12 and 23 litres. Smaller 2.5 gallon kegs 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 valves that are threaded into the keg, and after venting, can be opened by turning the valve counterclockwise using a piece of 1 3/4" wide metal inserted between the valve ears and turned with an adjustable wrench, or pipe wrench. A "wonderbar" type of pry bar just happens to fit. After the valve is loose it is still retained by a safety catch that must be pried inward. A simple valve seal depressing tool and a screwdriver with a 1/8"diameter shaft must be used to release the safety catch. See "How to remove a Miller threaded keg valve (not retained by a spiral ring)". The safety catch prevents the valve from releasing under pressure.
It is recommended that kegs not be sanitized with bleach to avoid unpleasant residuals. Iodine based solutions or specialty sanitizers such as Star-San 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.
See also
External links
- ""
- - A wikiHow article
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- Frequently asked questions on how to set up a keg of beer and how to maintain keg tapping equipment.
- : Match the beer brand with the correct keg coupler (keg tap) or keg pump.
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