My husband and I built a bread machine roaster, using an old Breadman brand from Goodwill, and a heat gun. He does the electrical and design, and I do the grunt-work and give advice as I do much of the reading/research for this project.
These are the modifications so far:
Disconnected the electronics and connected a simple on-off switch
Took out the BM heating element
Replaced the Teflon-aluminum pot with a stainless steel restaurant canister and lid (cheaper than what could be had at Goodwill, BTW)
Sandblasted the Teflon off of the mixing paddle
Cut 2 holes in the lid, added a stainless steel tube to bring the hot air down to the bean level
Added an adjustable connecting collar to support the heat gun on the tube at an angle
So far, this is working out pretty good. Roasts of 8 oz. finish to Full City in about 15 minutes, although I could turn up the heat and do it faster, but I think I have been reading that that isn't necessarily a good idea.
We will be adding a thermometer/thermocouple here soon, to get a better idea of what is going on in there. Right now I shine a light into the exhaust hole and check the roast every minute, or even half minute, as the roast is browning. Since the addition of the support for the heat gun, now I can write my notes, use the flashlight, using both hands.
The beans fly around inside so much, I wonder if these bread machines are more like air roasters, but slower, more controllable.
An idea which failed: protecting the air intake holes on the heat gun with window screen so the chaff couldn't get sucked into the gun. It slowed the air down to the point where I had a 40 minute bean-bake. Probably didn't do the heat gun any good, either. The beans smelled awful in a few days, huge difference.
Hi Martha, nice looking rig! Sounds like you've got the majority of the modding accomplished and are in control of this baby. Great work! Let us know how the coffee's tasting and shoot us any questions that come to mind.
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
Thanks Allen and John,
Well the roasting is going along pretty well, but I look forward to adding the thermocouple gizmo. My husband says it is all ready for me to drill the hole in the lid, but with Thanksgiving and house guests all that got put off. Maybe this week we will put it in, then I suspect husband will want to hook it up to a laptop so we can watch a graph in progress. He loves all technology.
My roasts have been ok lately, always too many variables changing to really know what is going on. I have about 10 types of single origin beans I use. Some beans go from 1st crack rapidly to second, some never start second...it is so hard to hear second crack with the heat gun and the bread machine going. But at least the roasts are far better than what I got out of the wok on the beer-making burner. I figure now if I can get the beans to Full City then out of there before Vienna, it is a success!
I'll post a picture of the roaster actually in use on the patio.