Steam mixed air retort is an overpressure system that can be used for flexible and semi-rigid containers. Steam and air ratio is a critical control factor during processing. This retort system can be applied to use only pure steam for metal can container. Steam-air retorts are normally operated at steam-air ratios ranging from 75% steam/25% air to 95% steam/5% air, depending upon the air over-pressure in the retort. Temperature distribution and heat transfer distribution test are necessary to perform in this retort.