• 02.01.05

Mr. Bubble: Gareth Halliwell

A Welsh engineer takes Guinness’ “widget” from the lab to production.

Time was when the only way to get that creamy head on a glass of Guinness stout was at a pub. But thanks to the “widget” — a plastic capsule that initiates a surge of bubbles when a can of Guinness is opened — draught-style Guinness has been available to home drinkers since 1988.


The man largely responsible for that is Gareth Halliwell, a Welsh engineer tasked with taking the widget from lab to production. “Making it work for one can of beer was simple,” he recalls. “Doing a thousand cans a minute was harder.”

One problem: Each can had to receive a globule of liquid nitrogen, which would turn to gas when the can was sealed and create pressure to force beer into a tiny hole in the widget. When the can was opened, beer in the widget would stream out of the hole, initiating the surge of bubbles. “But at high speed, the nitrogen globule kept missing the can or bouncing off,” says Halliwell. “We ended up spraying nitrogen at the line of cans.”

Another challenge was the widget’s 15/1000-inch hole. “You think a hole is a hole, but should it be circular or conical or square?” says Halliwell. “At one point, we tried laser-burning it, but we were melting widgets and burning conveyors. So we made the hole part of the widget’s casting.”

Guinness’s widget has been updated several times and inspired many copycats from rivals. But Halliwell, now stationed in Jamaica with Guinness’s sister brand Red Stripe, is still proud of his legacy. “There were endless problems,” he says. “But we solved them one by one.”