The invention is directed to a device (1) and a process for dissolving a gas into a liquid like carbonating a water based beverage, comprising a pump (4) for the liquid, a mixing venture nozzle (8) with a main inlet (10) fluidly connected to the pump (4), at least one side inlet (14) connectable to a source of pressurized gas (6), and an outlet. The device (1) comprises also a conical flow restrictor (24) fluidly downstream of the mixing venture nozzle (8), and a pipe (20) of a length of at least 0.5 m fluidly interconnected between the mixing venture nozzle (8) and the flow restrictor (24).