What types of machines are used to roast coffee beans?
There are 6 types of machines used to roast coffee beans:
- Drum roaster
 - Hot-air roaster
 - Fluid-bed roaster
 - Packed-bed roaster
 - Tangential roaster
 - Centrifugal roaster
 
The two most common types of coffee machine roasters are the drum roaster and the hot-air roaster. Each type of coffee roasting machine has its own set of benefits and drawbacks.
Drum Roaster

Drum roasters are cylindrical metal drums that continuously rotate over a heat source and slowly roast the green coffee beans inside. Most drum roasters provide an indirect source of heat, but some of the original drum roasters utilize a direct-fire heat source where the flame comes in direct contact with the coffee beans.