During continuously casting metal strip, delivering molten metal supported on the casting surfaces of the casting rolls, and counter rotating the casting rolls to form metal shells on the casting surfaces brought together at the nip to deliver cast strip downwardly with a controlled amount of mushy material between the metal shells, determining at a reference location downstream from the nip a target temperature for the cast strip corresponding to a desired amount of mushy material between the metal shells of the cast strip, sensing the temperature of the cast strip cast downstream from the nip at the reference location and producing a sensor signal corresponding to the sensed temperature, and causing an actuator to vary the gap at the nip between the casting rolls in response to the sensor signal received from the sensor and processed to determine the temperature difference between the sensed temperature and the target temperature.