Abstract: A beverage dispensing system has a valve in a tap controlling dispensing of the beverage through a first passage from a second rigid or flexible container. Air, nitrogen (or other inert gas) or carbon dioxide gas from a passage is introduced into the beverage in the first passage during dispensing for development of a head of froth. The introduced gas flows under pressure (which is preferably adjustable) from the second passage and by way of a capilliary tube restrictor and a non return valve communicating with the tube into the beverage in the first passage. The non return valve has a resilient diaphragm which normally closes that valve and is displaceable under gas pressure to admit the gas to the beverage. A labyrinthine mixer is located in the first passage downstream of the position where the gas is introduced.