A device for preparation of a liquid such as milk with integrated rinsing system includes at least one reservoir for storing of the liquid, disposed in a cooling unit, a pump and a line system, which system includes a liquid suction line, via which the at least one reservoir is connectible to the pump, an outlet line, via which the pump is connectible to at least one outlet, and a rinsing line, via which the liquid suction line is loadable with a rinsing fluid, and an air volume controller, by which air, via an air supply line, is able to be led in a metered way to an inlet point into the liquid suction line, and a heating element designed as continuous-flow heater, which is disposed in the outlet line and is designed as thick film heater. The device has in the air supply line a second check valve and a first check valve, disposed between the air volume controller and inlet point into the liquid suction line, and the air supply line is connectible between first check valve and second check valve to the rinsing line via a valve.