dream machine


New member
May 7, 2005
New Jersey
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Hello Coffee Roasters:

This is my first time here. From reading all the posts, I believe I came to the right place. Hopefully someone (hopefully everyone) can help me.
I am not a roaster. I design and build industrial machines for a living. But my brother is a coffee roaster and has a 7 pound capacity machine now. He is looking to acquire a machine to roast at least 20Kg, but the cost is out of his reach at this time.
I'm thinking "@hit, its just a steel drum on its side with a fire under it". How hard can it be to design and build that?? But to build one that roasts GOOD coffee might not be 1,2,3; you're done. To avoid the cost of a "trial and error" method, I was hoping to get some input from people who know a good design from a bad one. How their machine works and how they wish it were better.
I was just going to take my brothers existing machine and scale it up. The problem is; he is in Colorado and I'm in New Jersey. So I don't have one to take apart and see what makes it tick. Only pictures and his description.
So my question to this group is...If you could design your perfect machine, what would it look like? I have questions like:
1) what gage metal is the drum made of? (how thick)
2) are the carbon monoxide gases from the heating flames actually drawn into the drum with the roasting beans? (if so, yuck!)
3) is there a seal between the rotating drum and the stationary front and back walls? if so what material is it made from?
4) how are the roasted beans expelled?
This is my best guess at this time to make a 20kg roaster...
The drum is made from 16 gage steel (.059 thick) (about the thickness of a penny) 22" diameter by 28" long. Use up to 250,000 BTU's natural gas. Forced fresh, heated air (~500°) into the drum @ ~500CFM to keep a positive pressure of hot air on the tumbling beans. Drum RPM of ~30. A few thermometers here and there, a sample taker, glass window (pryex)
What are the dimensions of your machine? How could it be better? Any suggestions/opinions or caveats would be appreciated.
PS: No, I will not infringe on anyones patent. I have searched the US Patent data base. No too much there; can't patent fire or the wheel.
A self-cleaning, self-loading 100KG roaster w/ afterburner and full coverage for life warranty, all under 5 bucks.

Let me know when you get it together because I'll take two!