Draught beer from a pressurised keg is the most common method of dispensing in bars around the world. A metal keg is pressurised with carbon dioxide (CO2) gas which drives the beer to the dispensing tap or faucet. Some beers may be served with a nitrogen/carbon dioxide mixture. Nitrogen produces fine bubbles, resulting in a dense head and a creamy mouthfeel. Some types of beer can also be found in smaller, disposable kegs called beer balls.
In the 1980s, Guinness introduced the beer widget, a nitrogen-pressurised ball inside a can which creates a dense, tight head, similar to beer served from a nitrogen system.[135] The words draft and draught can be used as marketing terms to describe canned or bottled beers containing a beer widget, or which are cold-filtered rather than pasteurised.