Abstract: An apparatus is provided that is suitable for puffing a variety of different cereal material such as any cereal grain or cereal doughs or extrusions. A generally frusto-conical pressurizing chamber is provided with a nozzle component at its discharge end portion, which nozzle component is interchangeable with nozzle components having differing shapes and sizes depending upon the particular cereal material to be puffed or expanded. Steam injectors are tangentally oriented with respect to the pressurizing chamber, and they cooperate to provide a generally vortex-like discharge path for the cereal material out of the pressurizing chamber.