Abstract: A cryogenic freezer apparatus for food products includes a conveyor within a thermally insulated enclosure. A cryogen injecting unit is located in said enclosure adjacent the opening thereof, and responsive to a cryogen control signal for introducing liquid cryogen in said enclosure. A blower unit in said enclosure directs cryogen vapor away from said enclosure opening toward the interior of said enclosure. The output of said blower unit being controllable by a blower control signal. A sensing unit within said enclosure senses the cooling capacity of the cryogen vapor at the enclosure opening and generates a sensor output signal which is indicative of the amount of cryogen vapor escaping out of said opening. A control unit, coupled to said sensing unit, said injecting unit, and to said blower unit generates a cryogen control signal and a blower control signal in response to the sensor output signal.