Here's my fluid bed roaster build, inspired by [anonymized]'s cheap and tiny version. I took some other inspiration from a couple other builds on the home roasters forum also.

I'm using the most powerful air pump I found on Amazon (I believe the same one renetoa is using) and the HAS-043K element for the base components. The pump is rated for 39 cfm, whether that's true or not is another thing. The roast chamber is a standard Bake-A-Round and cocktail shaker lid, cutting through some frying pans, just like keving, all held together with threaded rod with a sleeve of stainless tubing to look pretty. The heating element is sitting in a chromed brass sink extension tube. I have the whole setup from Jim (TC4, ZCD, and LCDapter) controlling the fan and heater via Artisan. I am reusing some cherry wood from an old high school shop project for the case. This roaster is being used on a dedicated 20 amp circuit.

Roaster innards


Inlet air tubing (still needs to be finalized, TC installed, and sealed to fan)


Upper case housing the insulated heat tube (not pictured)


Perforated steel sheet for machine prettiness


Roast chamber sitting atop it all


I am able to use it functionally, but I'd rather finish up what I have left before diving in to roasting back to back batches. I need to sound deaden the box so it's not so noisy, first crack is tough to hear (plus I live in an apartment). I am a bit cramped in my lower compartment so I'm not sure if what little foam or insulation I could fit in there would make any noise difference other than increase the amount of heat. Speaking of heat, I have to run the fan with the box closed up so I can see if the fan temp gets too high. If so, I may need to put in a fan and cut some holes.

I am planning on recirculating the exhaust up to the PVC limit, but that will come later. I am fine playing around with 250g loads for now. I had tried 300g for my first trial batch and heat was an issue.

I will keep updating this thread as I add things here and there. Living in an apartment with little to no access to tools has stretched this build way longer than I wanted.

Thanks for looking!

Nice build!
If I may suggest, the recirculating to the heat limit of PVC will dramatically shorten its lifetime and expose coffee to smoke and potentially fumes from the PVC. My thoughts have run to perhaps using the exhaust as an insulator to the roast chamber itself by making it a double wall system?
Best wishes

Thanks Chris!
I misspoke when I said "heat limit", I am only planning on intake temps around 40-50°C. I had thought of running the exhaust through some sort of (non PVC) heat exchanger, but they are susceptible to fouling. I am going to give the recirc a try at 40-50°C and see how much larger a batch I am able to run. If it is minimal, I will scrap the recirc plans and focus on insulation and airflow efficiency.

This is an awesome build! I dig it!

How's the results so far?

I'd love to do something similar someday, especially for darker roasts and espresso blends.

Thanks Tom!

Results have yet to be determined. I have only thrown 300g of ancient grocery store Sumatra greens to season the roaster and I think the charge was a bit too much. I wanted to test and see how hot the heat tube would get and what insulation would be sufficient. I have since tore apart the roaster to finish running the inlet tubing and lower cabinet organization. Once that's done, I'll be able to roast a couple batches and keep the roaster more or less fully assembled and test different additions as I go.

Honestly, this is a super easy build for a non-perfectionist. If you want to quickly rig up a test bed it would perform well. I wanted a nice looking roaster that had lots of functionality, that came with cost of so much more frustration and time spent thinking and tinkering instead of roasting. If it looks pretty, my girlfriend won't mind if it sits out in the corner of our apartment instead of in the closet somewhere haha.

I like this a lot !! Can't wait to hear more results !!!

Honestly, this is a super easy build for a non-perfectionist. If you want to quickly rig up a test bed it would perform well

Easy for an engineer to say that . Wish I could have your mad skills. Beautiful build!!

jbenson4 wrote:Thanks Chris!
I misspoke when I said "heat limit", I am only planning on intake temps around 40-50°C. I had thought of running the exhaust through some sort of (non PVC) heat exchanger, but they are susceptible to fouling. I am going to give the recirc a try at 40-50°C and see how much larger a batch I am able to run. If it is minimal, I will scrap the recirc plans and focus on insulation and airflow efficiency.

Ah, fair enough! These are merely sketches in my mind based upon other works.
When I think about using the exhaust, I imagined a second glass cylinder (for visibility and cleaning) outside the bean chamber, with the chaff catcher at the base, so the exhaust flows up out of the bean chamber and down to exit at the base or vented elsewhere.
If you find a way to use glass or metal and smoke scrubbing, recirc is the go!