A cooking appliance that uses steam to heat a food item includes a cooking chamber; a steam generator that generates steam to heat the food item; a heating element that generates heat to heat the food item; an outlet that fluidly connects the cooking chamber to a first external environment outside of the cooking chamber; and an active inlet that fluidly connects the cooking chamber to a second external environment outside of the cooking chamber. The active inlet has a blocking member that prevents a fluid from the second external environment from entering the cooking chamber though the active inlet, and an actuator that moves the blocking member between a closed position in which the blocking member prevents the fluid from entering the cooking chamber through the active inlet, and an open position in which the blocking member allows the fluid to enter the cooking chamber through the active inlet.