Anatomy of a coffee roasting machine.
Today I'm starting a series of newsletters on the machine which lies at the centre of the Garage Roasters enterprise... without which the company would not exist... the coffee roasting machine.
You're probably aware that you can't just roast coffee in an oven. That's because beans need to move whilst being heated otherwise they scorch in areas where they make direct contact with high heat conductive surfaces. Scorched beans taste terrible in coffee.
So the most important function of a coffee roaster is to heat beans (both through conduction and convection) whilst keeping those beans moving.
Gas burners directly heat a rotating drum with vanes which keep the beans moving. The drum surface provides conductive heating to the beans. The burners also heat air which moves through the roasting chamber which provides convective heating.
With a skilled roasting professional at the helm, the result is delicious roasted coffee!
Over the next few weeks I'll be discussing the technical aspects of the various parts of the roaster:
Hopper
Drum
Sight glass
Trier
Thermocouple probes
Burners
Cooling tray
Damper
Chaff cyclone
Exhaust fan
Hope you're having a great week.