Two readings, two worlds. 馏 (second tone) is the chemistry word — distillation, as in 蒸馏. The kitchen reading 馏 (fourth tone) means to steam cold food hot again.
Left-side food radical, the running form of 食. It survives from the cooking sense (re-steaming food); the chemistry meaning 'distill' grew out of that same idea of heating to drive off vapor.
