Guinness Draught

Guinness Draught was the world's first nitrogenated beer. It reached pubs in 1959, Guinness's two hundredth year, after Michael Ash — a mathematician hired as the brewery's first non-brewer — spent most of a decade solving how to serve stout from a keg without wrecking it. His answer was nitrogen. It dissolves far less readily than carbon dioxide, so the beer can be pushed through the tap under pressure without turning fizzy, and the minute bubbles that result are what you watch surging and settling before the pint clears. The same trick reached cans in 1988 through a plastic widget that releases nitrogen the moment the can opens.