Шағын бөшкелер және сыра сақтау ыдыстары

Small barrel, commonly used for beer

A keg is a small cask. Wooden kegs made by a cooper were used to transport nails, gunpowder, and a variety of liquids. A keg is nowadays normally constructed of stainless steel, although aluminium can be used if it is coated with plastic on the inside. 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. Carbonated drinks are generally kept under pressure in order to maintain carbon dioxide in solution, preventing the beverage from becoming flat.

Beer kegs are made of stainless steel, or less commonly, of aluminium. A keg has a single opening on one end, called a "bung". A tube called a "spear" extends from the opening to the other end. There is a self closing valve that is opened by the coupling fitting which is attached when the keg is tapped. There is also an opening at the top of the spear that allows gas (usually carbon dioxide) to drive the beer out of the keg. The coupling fitting has one or two valves that control the flow of beer out of and gas into the keg. The keg must be in the upright position, that is, with the opening on top, for the beer to be dispensed. Kegs can be contrasted to casks, which have two or more openings and no spear. Most major breweries now use internally speared kegs. Beer that is sold in kegs is fully conditioned. Beer intended for local use may be kegged without sterilization, however, the beer must stay cold.

Historically a beer barrel was a standard size of , as opposed to a wine barrel of , or an oil barrel of Over the years barrel sizes have evolved, and breweries throughout the world use different sized containers. Even when the content capacity of two kegs are equal, e. g. metricized to 50 liters, the keg shape and tap system may differ greatly.

The Cornelius keg (also known as a "Corny keg" or "soda keg") was originally used by the soft drink industry. It is now commonly used to store and dispense beer, especially homebrewed. Cornelius kegs were originally made by Cornelius, Inc., and were used for premix soft drinks. 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. Cornelius kegs use two unique types of tap, both very similar to each other, known as ball locks and pin locks.

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 disposable kegs, being made of aluminum, may be recycled. In Canada, Molson brewery dubbed the mini keg "Bubba". This name has now been genericized to generally apply 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. Today, mini kegs are widely available in liquor stores worldwide, with Heineken, Grolsch and Bitburger all adopting the design. Recently in Austria, beer is available in mini kegs, either by a one way type keg made of steel or out of a reinforced thermoplastic for about a 4 € deposit.

Another type of mini keg is the "beer ball" or the "party ball", a disposable plastic ball that usually holds around , roughly the equivalent of 55 twelve ounce beers, though they can also be found in a smaller size. Like kegs, it is necessary to tap the ball before the beer inside can be served.

One way kegs, also known as disposable kegs or PET kegs, were invented in 1996. They are usually made of plastic. Some types have a cardboard outer packaging, which makes them easier to stack and transport, and also protects the plastic container. Some may use either bag in ball or spear technology. Products like the Hybrid keg have a puncture resistant wall and are easy to disassemble after use. Circular by design, the top and bottom chimes can either be re used or recycled.

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. It is half the size of the standard beer keg and equivalent to a quarter of a barrel. The term pony refers to its smaller size – compare pony glass (quarter pint) and pony bottle. 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. In some places, such as Cincinnati, the term pony keg can mean a convenience store that sells beer.

A sixth barrel keg contains approximately 5.2 gallons, and is becoming the choice for many establishments and breweries that wish to use kegs smaller than a half barrel. The sixth barrel kegs are nominally larger in size and volume compared to the Cornelius keg. They are normally fitted with a standard US Type D Sanke coupler on a single downspout; whereas, Corny kegs are normally fitted with a flip hatch, and a dual connector pin lock or ball lock top. Although the sixth barrel torpedo keg is approximately the same height as the standard half barrel, the smaller foot print of the sixth barrel allows retailers have a greater variety of beer in a small space. This size keg is quickly replacing the quarter barrel size which has the same foot print as a half barrel keg, but is only half as tall. Other than smaller circumference, sixth barrel kegs are very similar to their full sized counterparts in construction. A stainless Micromatic brand sixth barrel keg weighs approximately 14 15 pounds (6.3–6.8 kg) when empty, and approximately 58 60 pounds (26.3 27.2 kg) when full.

An eighth barrel has the same dimensions as a sixth barrel, but the seven bottom most inches are hollow.

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. The kegs themselves are made from stainless steel or aluminium. The standard keg size is 11 imperial gallons (50 litres/88 imperial pints) and the vast majority of keg beers are supplied in this keg size. There are also smaller 30 litre (≈52.7926 imperial pints) kegs usually reserved for more specialist and premium European beers. A number of manufacturers also produce 18 imperial gallon (81.82 litres/144 imperial pints) and 22 imperial gallon (100 litres/176 imperial pints) kegs, however owing to their size they are not as 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 output. For bars that sell a large volume of beer, there is the 36 imperial gallon (163.64 litres/288 imperial pints) keg. However, due to its very large size, few people can move it without assistance, making it an impractical choice otherwise.

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.