- “Snake tube” coil heat exchanger
A device made of drawn copper, aluminium or stainless steel piping in a spiral arrangement, formerly used for pasteurizing sake. The jakan is placed in a tank, steamer or the body of a fune press containing hot water, and sake is pumped through the piping to heat it. Today, the jakan has been almost entirely replaced by plate heater exchangers and other sterilizing equipment.
Improved versions of the jakan have a double construction, where heat exchange occurs between the inner and outer pipes. This type is also called a double-pipe heat exchanger, and is used, not only for pasteurization, but for cooling moromi or yodan by pumping cold water through the outer part.