A draft beer system is a setup used to serve beer from kegs rather than bottles or cans. It typically includes components like a keg, a tap, and a CO2 tank. The CO2 tank helps maintain pressure, pushing the beer from the keg through the lines to the tap, where it is poured into a glass. These systems can vary in complexity, from simple home setups to elaborate commercial installations found in bars and restaurants. Proper maintenance is essential to ensure the beer stays fresh and carbonated, preventing issues like flat beer or excessive foam when pouring.