Abstract: An apparatus and method of roasting foodstuff such as coffee beans employ a roasting chamber for roasting the beans. An air circulation system operatively coupled with the chamber flows heated air over the beans and thereby roasts the beans, and an air cleaning arrangement is operatively coupled with the air circulation system and located downstream of the chamber for removing substantially all particulates, smoke and volatiles entrained in the used air as it flows through the container and into the air cleaning arrangement to provide substantially pollutant-free used air. The circulation system uses atmospheric air and heats, cleans and cools it within as little as ¼ second. Sensors and a electronic controller are provided to monitor various parameters in the roasting apparatus and control the roasting characteristics. The darkness and/or color of the beans during roasting is monitored to ensure proper roasting.

Abstract: Bulk material formed by a multiplicity of individual moving particles is heat-treated by directing a light beam into an observation volume of the material and generating light reflections off at least one particle in the observation volume. A characteristic of the light reflections which is indicative of a desired extent to which the material is to be heat-treated is identified and the material is subjected to a heated environment and thereby heat-treated. The light reflections are monitored for the characteristic, and subjecting the material to the heated environment is ended in response to detecting the characteristic of the light reflections.