Created | Updated Jan 6, 2012
A widget1 is a device used to introduce nitrogen into canned beer to produce a firm head similar to draught beer.
The nitrogen is released into the beer when the can pressure drops after opening. The drink must be poured immediately to prevent the nitrogen escaping completely, as it is not very soluble in beer. The escaping nitrogen enables the formation of fine bubbles, resulting in an extremely stable head.
1The term 'widget' is used to describe any of an assortment of undefined tools, mechanisms, or concepts.