Draught beer

Draught beer (also known as draft beer or tap beer) has several related though slightly different understandings. The majority of references to draught beer are of filtered beer that has been served from a pressurised container, such as a keg or a widget can. A narrower meaning, beer that is served from a keg (or tap), but not from a can, bottle or cask, is also used. A more traditional definition is beer that is served from a large container, which could be either a keg or a cask. The different understandings may at times overlap and cause confusion. Some traditionalists object to the more modern use of the word when applied to canned beer. The slight usage differences of the term are due to the history and development of beer dispensing.

Until Joseph Bramah patented the beer engine in 1785, beer was served directly from the cask and carried to the customer. The old English word for carry was dragen, from the German tragen, which developed into a series of related words, including drag, draw, and draught. By extension, the word for carrying or drawing a beer came to mean the serving of the beer and, in some senses, the act of drinking, or a drink of beer itself, regardless of serving method. By the time Bramah's beer pumps became popular, the use of the word draught to mean the act of serving beer was well established and transferred easily to beer served via the hand pumps.

In 1691, an article in the London Gazette mentioned John Lofting, who held a patent for a fire engine: "The said patentee has also projected a very useful engine for starting of beer, and other liquors which will draw from 20 to 30 barrels an hour, which are completely fixed with brass joints and screws at reasonable rates".

In the early 20th century, serving draught beer from pressurised containers began. Artificial carbonation was introduced in the United Kingdom in 1936, with Watney’s experimental pasteurised beer Red Barrel. Though this method of serving beer did not take hold in the U.K. until the late 1950s, it did become the favoured method in the rest of Europe, where it is known by such terms as en pression. The method of serving beer under pressure then spread to the rest of the world; by the early 1970s, draught beer was almost exclusively beer served under pressure.

Shortly after a British consumer organisation called the Campaign for Real Ale (CAMRA) was founded, in 1971, to protect unpressurised beer, the group devised the term real ale to differentiate between beer served from the cask and beer served under pressure. By 2004, the term real ale had been expanded to include bottle-conditioned beer, while the term cask ale had become the accepted global term to indicate a beer not served under pressure.

Draught beer is usually unpasteurised in America. It is intended to be kept refrigerated between 2°C (35°F) and 4°C (40°F), and consumed quickly after being "tapped". Above 6°C (44°F), a beer may within two days turn sour and cloudy. Below 6°C (44°F), a keg of draft beer should last 20-30 days before it loses its fresh taste and aroma.