Abstract: A working fluid condensate cools hot containers within a pressure vessel in a process which includes condensing vapors of the working fluid on a cool surface within the pressure vessel and transporting the condensate onto the hot containers for vaporization therefrom to continue the process cyclically. In one embodiment, the condensate is transported by capillary flow through a wick which covers a portion of the container. In alternative embodiments, the condensate is transported from the cool surface to the hot containers by flow induced by gravity, pumps, or centrifugal force.The invention is applied to food processing in a pressure environment. For cleaning convenience, the food is confined to containers, yet short processing times are provided by condensation and vaporization of water as a working fluid which effectively exchanges heat between the containers and heat exchange surfaces within the pressure vessel.