Take the 2-minute tour ×
Homebrewing Stack Exchange is a question and answer site for dedicated home brewers and serious enthusiasts. It's 100% free, no registration required.

How do those N2 widgets work in cans of beers like guineas, tetleys and Old Speckled Hen? Is the N2 in the widget and released when the can opens, or is the N2 in the beer and the widget helps mix and froth the whole thing?

share|improve this question

closed as off topic by Nathan Koop Sep 27 '11 at 19:42

Questions on Homebrewing Stack Exchange are expected to relate to homebrewing within the scope defined by the community. Consider editing the question or leaving comments for improvement if you believe the question can be reworded to fit within the scope. Read more about reopening questions here.If this question can be reworded to fit the rules in the help center, please edit the question.

add comment

1 Answer 1

up vote 4 down vote accepted

http://en.wikipedia.org/wiki/Widget_(beer)#Method

When the can is opened, the pressure in the can quickly drops, causing the pressurised gas and beer inside the widget to jet out from the hole. This agitation on the surrounding beer causes a chain reaction of bubble formation throughout the beer. The result, when the can is then poured out, is a surging mixture in the glass of very small gas bubbles and liquid.

...so, if I understand correctly, the widget contains liquid nitrogen when bottled. After bottling the widget raises in temperature and pressurizes to match the pressure of the can. When the can is opened the can drops in pressure and the nitrogen spews out of the widget, stirring the beer into a nice creamy head.

share|improve this answer
1  
I am trying to wrap my head around the use of the liquid nitrogen and how the gas stays in the ball during filling and post filling. Pressure alone (at least at the can level) isn't enough to keep the nitrogen in a liquid state. So it must evaporate to a gas post fill, staying in the ball is still the mystery. But a great answer indeed. –  brewchez Dec 2 '10 at 12:52
add comment

Not the answer you're looking for? Browse other questions tagged or ask your own question.