Abstract: An apparatus and method for measuring coolant quenching rates includes a metallic disk supported on a ceramic tube, the metallic disk including a plurality of thermocouples therein. The metallic disk is heated from above by a torch and coolant is sprayed on the underside of the disk. Changes in temperature throughout the metallic disk are detected by the thermocouples to measure various quenching parameters. The metallic disk may be surrounded by insulating material to maintain heat flow through the disk in a predetermined manner. By heating, insulating and cooling the metallic disk, temperature measurements can be quantified into heat transfer rates to investigate various heat transfer mechanisms and different types of coolants.