Guinness from a can tastes better then it used to be because they have something called a 'Widget' in each can - It is a small plastic sphere with a small hole in it. The sphere is manufactured so that it will float with the hole just below the surface.
The Guinness is made with some CO2 dissolved in it and is put into the can. The widget is filled with nitrogen and put in the can to float on the top of the Guinness. A small shot of liquid nitrogen is added to the can just before the top is put on and the can sealed.
The liquid nitrogen evaporates to form a gas and pressurizes the can. This forces Guinness, with dissolved CO2, into the sphere and the nitrogen in the sphere maintains a pressure equal to the pressure in the can.
When you open the can, there is a sudden drop in pressure and the nitrogen in the sphere forces the Guinness out through the small hole. The CO2 dissolved in the Guinness being forced out of the hole forms bubbles as it leaves which forms the head. Guinness contains a higher proportion of solids than other beers which accounts for it's long lasting head.
The Guinness is made with some CO2 dissolved in it and is put into the can. The widget is filled with nitrogen and put in the can to float on the top of the Guinness. A small shot of liquid nitrogen is added to the can just before the top is put on and the can sealed.
The liquid nitrogen evaporates to form a gas and pressurizes the can. This forces Guinness, with dissolved CO2, into the sphere and the nitrogen in the sphere maintains a pressure equal to the pressure in the can.
When you open the can, there is a sudden drop in pressure and the nitrogen in the sphere forces the Guinness out through the small hole. The CO2 dissolved in the Guinness being forced out of the hole forms bubbles as it leaves which forms the head. Guinness contains a higher proportion of solids than other beers which accounts for it's long lasting head.
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