K is for Keg
K is for Keg – part 11 of our A to Z guide to craft beer terms.
Precious vessels of beer, pressurised kegs have been serving up carbonated brews since the early 1900’s. Before that, your local would pour your beer directly from the barrel.
Though the use of artificial carbonation (also called forced carbonation) was introduced in the UK during the 1930’s, it took another 40 years before the terms “draught” and “draft” referred exclusively to beer which was served under pressure as opposed to hand pulled from casks or barrels.
Before Devil’s Peak puts its beer into keg, we force carbonate and filter it. Filtering removes most of the yeast and ensures the keg does not become over carbonated – leading to a pint full of foam and unhappy bartenders.
Though kegs come in many shapes and sizes, they all basically work in the same way.
A large sheet of stainless steel is rolled into a cylinder, welded and reinforced for added durability and safety. A propriety blend of metals is used to ensure a smoothness that allows the kegs to achieve a food-grade rating. You can’t have rough spots or imperfections in the metal where bacteria can latch on and grow.
A long, metal tube called a spear is fitted through the top of the keg. Acting almost like a straw, it reaches down to just above the bottom of the container. On top of the spear is a valve. This valve is connected to a beer dispenser and gas source via a device called a coupler. Depending on the keg manufacturer, country and brewery preference, couplers and the valves can vary in size and shape (much to the annoyance of bars and restaurants). So a Devil’s Peak coupler might not fit onto a keg from Bob’s Beer, which uses a different valve for their spear.
Once coupled, the keg is ready to be used. As the tap of a draft machine is opened, the coupler allows beer to flow out of the keg via a beer line while gas is fed into the keg via a second line. Once the tap is closed, the beer stops flowing, pressure equalises inside the keg, and you’re ready to pour another pint!