a coffee bean roasting system is disclosed wherein coffee beans in a box - like chamber are levitated as a dense , uniformly recirculating mass by an upwardly directed airstream . the air is heated to a temperature not in excess of 530 ° f ., and the heat is transferred to the beans primarily by convection and secondarily by conduction from bean to bean . heat transfer continues until after a thermally induced pyrolitic reaction has occurred within the bean mass and the desired roast has resulted whereupon the roasted beans are cooled . the system may employ batch type or continuous roast apparatus .