Intentional operation of a boiler, furnace, oven, etc., at a low level. / The state of not burning fuel at the desired level, and thus not providing heat efficiently.

present participle of underfire

(comparable, ceramics) Fired at a low (or excessively low) temperature. / (not comparable, cooking) Of a cooker: having a heat source that is underneath the food being cooked.

simple past tense and past participle of underfire

Third-person singular simple present indicative form of underfire

(transitive, intransitive) To heat from below. / (transitive) To intentionally operate a boiler, furnace, oven, etc., at a low level.