How do Beer Kegs Work? - All About Kegs - Draught Beer Explained
The kegs themselves work kind of like a can of soda or pop but with a massive straw .
All About Kegs - Draught Beer Explained:
Inside the keg, there's a long tube of metal extending from the valve to the vessel's bottom. To get beer out of the keg, gas pressure is applied to the top surface of the liquid, which presses the beer from the bottom of the keg up through that metal tube and out of the valve.