The invention relates to a cooking appliance (10) comprising a cooking chamber (11) with heating elements (12) and a water supply (30) that has a water outlet (33) and is fed by an outer water supply line (40). The water supply (30) is provided with at least one intermediate water storage tank (45) with a pre-determined inner volume (46) that can be filled with water and is fed by the outer water supply line. The filling and emptying of the inner volume (46) of the at least one intermediate water storage tank (45) can be temporarily blocked by means of a three-way valve or two-way valves. The water from the inner volume (33) of the at least one intermediate water storage tank (45) can be emptied via the water outlets (33) in order to generate steam in the cooking chamber (11). The emptying of said at least one intermediate water storage tank is especially periodical or clocked. The intermediate water storage tank can be embodied as a lifting cylinder that is filled and emptied by the lifting movement of a piston (48).