MY BUILD OF THE COFFEE ROASTING BARREL
The roasting barrel is constructed from two stainless steel kitchen colanders and driven by the rotisserie on my grill. It does the job well and is capable of roasting up to 4 pound batches. Internal baffles ensure beans are well mixed as they tumble and also direct the beans to empty out the door after roasting.
Landing on the idea of joining two colanders for the barrel satisfied a good number of design requirements. The perforated thin gage stainless steel bowel shapes can be joined to form a barrel able to roast coffee as well or better than any roaster out there selling for $100s online.
Because of the high temperature operating conditions, all the roasting barrel components are stainless steel except for a few aluminum parts. My original plan was to TIG weld the all the stainless but as you can see, my welding skills weren’t up to my ambition. Using thick walled tubing, dowel rod and bar stock, I cut and was able to weld-up the hinge and latch components. I did not attempt welding to the thin walled colandar. Instead, small fasteners with metal locking nuts were used for bolt connecting components to the colander. Aluminum bar stock is used to bolt colander halves together and aluminum angle baffles are bolted to inside wall of the barrel.
Construction began by cutting out the door halves using a thin blade grinder.
After welding and drilling the hinge and latch parts, assembly was a matter of loosely bolting parts together, squaring things up and then tightening fasteners with a screw driver. Metal lock nuts inside the barrel conveniently grip without need of a wrench. The two piece door comes together rigid and travels as a single door. In fact, the entire barrel is quite rigid and certainly doesn’t dent when getting knocked around.
I used a sharp punch, rather than drilling, to cut fastener openings through the thin metal. Punching against the end of a wooded stick will minimize denting.
Latch pin is a simple dowl rod with a grip form on one end.
One advantage of this project is that it allows you to capitalize on existing equipment, assuming you have a rotisserie on your grill. The barrel is center mounted onto a threaded rod with ends modified to be driven and supported by the rotisserie.
The rotisserie drive motor accepts a hex bar so the driving end of threaded rod requires grinding or filing flats onto the end of the threaded rod.
The guided end of the rotisserie is a simple support bracket. On this end, the threaded rod is double nutted and threads ground or filed smooth at the support bracket location.
This is a well used coffee roasting barrel with door open exposing the internal baffles that ensure beans tumble within the barrel when roasting. The baffles also direct beans out the door when roasting is complete.
There are many places on line to buy green coffee beans. I have been quite happy with sourcing from Sweet Maria’s. https://www.sweetmarias.com
My only complaint regarding this project was the high pitched squeaking caused by metal sliding on metal as the guided end of the threaded rod turns on the rotisserie support.
The solution to the noise issue was finding some high temperature bearing material and fitting a bearing to the existing support. I did this with 1/4in graphite sheet obtained from www.mcmaster.com
The annoying squeaking noise disappeared with the installation of this high temperature graphite bearing supporting the guided end of the barrel.