A sparging evaporator for an inerting system including an outer vessel, an inner vessel within the outer vessel, and a plenum formed between the inner and outer vessels. The outer vessel includes a gas inlet for receiving inlet gas into the plenum, and a liquid inlet for receiving liquid fuel into the plenum. The inlet gas in the plenum generates a gas pressure that is exerted against a free surface of the liquid fuel in the plenum thereby forcing the liquid fuel and the inlet gas through an inlet of the inner vessel. The inner vessel contains a structure that promotes liberation of fuel vapor from the liquid fuel and enables the inlet gas in the liquid fuel to sparge the fuel vapor in the liquid fuel, thereby forming a fuel-enriched gas mixture that can be fed to a reactor of the inerting system.