Eli5: What’s that widget in the Guinness can up to? (Other stouts are available…)

Question

Why does stout need the widget and what’s it doing in there?

In: 3

Answer 1

Adds nitrogen bubbles to your beer. Most other beers have carbonated bubbles either from fermentation process or injected before or during the bottling process.
Nitrogen bubbles give a softer mouth feel, makes Guinness taste more creamier.

I don’t know the process of getting the widget into the can with the beer but the nitrogen gas in the widget would be under lower pressure that the beer in the can. When the can is opened the pressure in the beer can drops allowing the nitrogen gas from the widget to inject into the beer.