Roasted coffee bean by charcoal fire

Charcoal fire gives coffee special flavour. It takes about 9 minutes to roast 500gram of fresh bean. Poured out in the middle of first crack. It is something like medium roasted. You can hear clearly the crack voice. The drum is driven by a 12 V DC 30 rpm motor. Charcoal fire is controlled by a 12 V DC 10 cfm blower. Blower can be tuned by hands, in turn the fire strength. Electricity is supplied by 3 pieces of rechargeable battery 18650. Lesson: the blower is too strong, so the fire. next time I shall tune down blower to roast in 15 minutes. Slow roasting will be much more even