An inflator that includes a quantity of gas generant housed within a chamber. A liquid and a piston are also housed within another chamber. This chamber is sealed by a burst disk. The piston includes an opening. During deployment of the inflator, the burst disk is ruptured and the piston moves towards the distal end of the inflator. The movement of the piston hydraulically expels the liquid through the opening in the piston such that the liquid cools and contacts the gas formed by combustion of the gas generant.