Rather than rotating the drum to move the beans, a fixed-drum roaster uses mechanical paddles to stir the beans within the roasting chamber. This type of design harks back to the early days of coffee roasting, in which a person held the beans in a pan over a fire and stirred them with a spoon. Many early domestic roasting devices used a fixed pan with a mechanical stirrer that could be set over a fire.
A domestic roasting device using a fixed drum with a mechanical stirrer
When heated directly over the flame, a fixed drum has a high risk of causing bean-surface burning, as the surface closest to the flame can become very hot. With the development of hot-air roasting,