Coffee Roaster Prototype

By admin, December 6, 2014

Coffee roaster prototype enhances friend’s homebrewing facility.

Coffee roaster prototype

Friend reviews the coffee roaster prototype

A friend who passionately experiments with homebrewing and coffee roasting asked me to design a coffee roaster prototype for his experiments.

After online research and multiple visits to a local shop with a Probat roaster, I created a 3D CAD model of my proposed design.

3D CAD coffee roaster

Coffee roaster prototype developing in 3D CAD

After refining the model, I ordered laser cutting of prototype sheet metal and started machining and fabricating parts myself.

Bending brake

Bending sheet metal for trays

Cooling tray

Completed cooling tray and chaff collector

Lathe work

Machining bushings for drum supports

Drum back screen

Rear screen for my drum

In June we did our first roasting trial. While the very first run produced a minor fire scare due to bean escapes, the second one gave us usable coffee!

First roasted coffee

Output from first successful roast

We took what we learned and I refined a few things for the second session:

  • installed a proper front door with a bean sampling port
  • changed front thermocouples to get a better measurement of bean temperature in the drum
  • cut down the drum baffles to get thermocouple deeper into roasting beans
  • added a bean deflector to keep beans out of exhaust duct
Front Updates

Front end updates before second roasting session

We are generally pleased with how the roaster prototype works. We are currently considering further mechanical refinements to shrink the size, simplify assembly, and reduce the cost of the roaster.