In a direct draw beer system (approximately 5‚Äô run from keg to faucet) the beer line is only 3/16‚Äù ID. This narrow diameter along with the length of tube is known as restriction. Only use a vinyl hose that is approved for beverage dispensing, and preferably brewery approved. In general, the longer the beer line is, the lower the serving pressure at the faucet. If the faucet outlet pressure is too high or too low, the overall system is said to be out of balance and your beer will either foam or be flat.