Hail to the widget!

When we poured both the Guinness Draught and the Murphy's Stout, we heard a little rattle in the can from a contraption that Guinness calls a widget and Murphy's calls "a floating draughtflow system device." Whatever the name, the device consists of a plastic, nitrogen-filled ball with a tiny hole. It's added just before the can is sealed and floats in the beer. It's there because stouts, although less carbonated than most beers, are supposed to have creamier, longer lasting heads--something a good bartender can easily achieve when drawing the beer from a tap. The problem when stout is canned or bottled, however, is that the combination of the carbon dioxide and nitrogen needed to create this "head" and the lower carbonation of the beer results in too little "fizz" to produce and maintain a creamy, foamy head. When a can or bottle containing a widget is opened, the compressed gas in the widget helps the carbon dioxide already dissolved in the beer form additional tiny bubbles, which keep the head stable.