Steam kettles have an extra jacket on the outside of the main bowl which is either permanently sealed with water or can be hooked into a building’s steam lines. For permanently sealed models, the steam can be produced using either gas or electric burners. Direct steam models are ideal in buildings with a centralize boiler. Since the steam does not come into contact with the food, it does not have to be food safe for direct steam models. The kettles that can be manually tilted are easier to completely empty. They also help employees reach inside for a thorough cleaning.