Coffee beans are cleaned using air classifier & passed through destoner. Blend of beans or chicory is roasted in continuous or batch type roaster. The continuous roaster is a long perforated cylinder (3/16 “in holes). Several feet in dia with an internal spiral sheet 200 mm high. The coffee beans are compartmented into 100 to 150 mm spacing of spiral. Hot gas passed through the cylinder wall perforations are sufficiently forceful & turbulent to pass through few millimetres of beans with good heat transfer. The coffee beans ride the upward movement of the perforated cylinder wall & tumble back upon each other. The roasting process occurs progressively along length of cylinder. The roasted beans continue to spiral through with a heat lock or centre disc separating the heating from the cooling parts of cylinder.