One fills the bottom with boiling water and places the food to be cooked in the top one. The top pot is kept above the boiling water and heated only by steam, but tight fitting of the two pots prevents steam from escaping.
WIPO ASSIGNS PATENT TO OCOO FOR "COOKING METHOD USING AN AUTOMATIC PRESSURE-CONTROLLED DOUBLE BOILER" (SOUTH KOREAN INVENTOR)
Jul 30, 2011; GENEVA, July 30 -- Publication No. WO/2011/090326 was published on July 28. Title of the invention: "COOKING METHOD USING AN...