Enameling steels that had exhibited various degrees of reboiling behavior after ground‐coat enameling were charged with hydrogen to saturation by immersion in 2Nsulfuric acid at 38° C. Hydrogen contents were then determined by warm extraction at 160° C. under mercury. It is shown that for a given grade of steel the specimens which had been rated as heavy reboilers in the enameling tests occluded at 38° C. considerably less hydrogen than those rated as trace or light reboilers. A given level of hydrogen solubility, however, does not necessarily indicate the same reboiling tendency for different grades of steel. The determination of hydrogen solubility by the techniques described provides a method of indicating the reboiling tendency of a particular steel that is independent of the effects introduced by ground‐coat compo