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Veni - vidi - hello popper!
Billy Bean
Top  #1 Print Post
Posted on 01/05/2025 2:31 PM
Hello all, I am a newbie on coffee roasting, drank Costco Kirkland dark Columbian pre-ground for at least 30 years using a normal drip machine. Two weeks ago, I bought an expresso machine and with the research on it I came across many articles about roasting yourself and the high(er) quality it would give (if you do it right lol). I am a single guy so I am not looking for big volume, more on a regular base fresh bean and oh, I also have a great coffee grinder that I used for spices in the past. I like this challenge as I made my living in the past with innovation. The version I have in mind, I haven’t seen it yet in my research, I will update this post with updates after each development.

Here we go:

I bought a “straight shooter”, you know, the one that nobody recommends, 1200W, I have added 2 images.

infento.design/grinder/1.jpginfento.design/grinder/2.jpg

1. On the last day of the year I did my first test with 30 gram green beans in the popper and hurray it was like fireworks, most of the beans were shot 8 inches out of the popper, that made me think.

2. Second test (40gr) was the next day and I placed a chimney from an oil lamp on the popper, that went very well, I lost only 1 bean. The “belly” of the chimney has a bigger volume so the air-speed decreases in that area and the beans drop. I let the roast continue with the heat and airflow as it was and I got the first crack in 2.5 minutes and I was done in 3.5 minutes. I got a nice even dark roast but without any flavor profile development, it tasted like my Costco coffee.

infento.design/grinder/3.jpg

3. I did a temperature test with a thermocouple and voltage controller, see image. The thermostat from the popper shuts off at 440F, which is great (I think).

infento.design/grinder/4.jpg

4. Next test (50gr) was an intermitting test. Still nothing changed on the output of the popper but I placed an on/off timer in-between and set it on 20 seconds “on” and 20 seconds “off”. That went surprisingly well. I had to shake the popper the first minute. After 2 minutes the beans were yellow and at 4.5 minutes I heard the first crack. I stopped the roast after 7 minutes. The roast was not perfectly even, see image, but OH BOY, that was good coffee!

infento.design/grinder/5.jpg

I think the “unevenness” is caused by the intermitting effect. The beans at the bottom stay in the hot area for 20 seconds before to move again and this happens several times.

This gave me the confidence to keep going.
The plan for the next test will be adding an external adjustable air pump, to be continued. Cheers.
Edited by Billy Bean on 01/12/2025 5:25 PM
Never delay what you can do today....
 
renatoa
Top  #2 Print Post
Posted on 01/06/2025 3:34 AM
Hi, and welcome !
This is close to how I started... (too) Grin many years ago... using manual on-off.
The main difference was the switch rate was much faster, probably in the 3-4 seconds ballpark, as I remember.
Was fun for the first roasts, but became quickly impractical and annoying to stay focused so many minutes, thus added an external dimmer for the heat.

Regarding what you intend to be the next step... why an external air pump ?
Want more beans roasted? More airflow will not help adding too much, is the roast chamber diameter the limiting factor. Adding a tall chimney helps to avoid beans spill, but not to evenness of heat.
 
Billy Bean
Top  #3 Print Post
Posted on 01/06/2025 4:27 AM
Txs for your reply. The timer was only a temporary solution for myself to see the difference with a longer and “more evenly controlled” roast, even if it was intermitted.

I am a “see and feel” guy, I’ve read for days about roasting in a modified air popper but I need to experience it myself and learn from it.

I DID (try to) install a dimmer but I blew the electronics, that was also “see and feel” Grin. And as I live in the middle of nowhere, I had to drive through the snow to Ottawa to get another one (3 hours up and down). I was lucky I found the same one.

So I decided not to mess with the electronics and ad the external air pump. I have tons of “stuff” from previous ideas/tests on the shelf so I try to use what I already have. It is not that I want to stuff the popper full with beans, I would like to go to maybe 80 – 90 grams of fresh beans that would give me 70 – 75 roasted beans.

The external air pump has 3 advantages for me;

1 – I can load a bit more as with 50 grams I need to “shake” the popper in the beginning.
2 – It is easy to adjust the start-up when I would have bigger (heavier) beans.
3 – This is last but not least, I can cool the roasted beans IN the popper. I simply close the popper itself but keep the external air pump running.

I know I have a lot to learn but I like to try things out, even if it is not always a success the first time, but I am used to that.


infento.design/grinder/6.jpg
Never delay what you can do today....
 
renatoa
Top  #4 Print Post
Posted on 01/06/2025 7:37 AM
The last point above needs a bit of detailing...
There are two ways how motor in poppers is powered... let's call them serial and parallel.
> Mostly EU models are using the serial connection... the heater resistance is divided into two sections having approximately 1:10 ratio, such way that the 230V mains voltage is divided across these sections something like 20+210V.
The motor is connected to the 20V section... as a result it can't operate independent from the heater. You can't spin the motor to cool the beans, because the heater must be on, to provide the 20V required by the motor.
> For many US models, this connection is different, the heater and motor are both connected to mains on separate parallel circuits, so you can cut either the heater or the motor independently... a warning though: without airflow the heater will overheat and finally will melt/fire the case.
Another note for the US models... the motor still requires a resistance to drop the voltage from 115V to ~20V... and this resistance is part of the heater... so a complete cooling down to ambient can't be performed in the machine... but what we get, about 70C temperature after 2 minutes, is satisfactory enough to be able to touch the beans and continue the cooling outside the popper in a strainer/colander.

Tu sum the above, to cool the beans the EU guys needs either an external cooler, either power motor from a separate source... while the US guys could be fortunate to have a parallel motor powered model, that can be turned into a cooler just pressing a switch.

No idea how is wired this popper you are using, but maybe you find this info interesting enough to inspect the wiring and tell us what we have on the table.
 
Billy Bean
Top  #5 Print Post
Posted on 01/06/2025 8:22 AM
It’s much simpler than you assume, I keep the motor powered. I did not take out the motor of the popper, the popper is still in original shape. If I pull the popper switch to start the roast, both, original motor and heating work and additionally I can feed a bit of extra air by the external air pump. If the beans get lighter, I might lower the additional air and if the roast is done, I pull the popper switch (motor and heating off) and I can cool the beans with the external air pump.

infento.design/grinder/7.jpg
Never delay what you can do today....
 
renatoa
Top  #6 Print Post
Posted on 01/06/2025 8:36 AM
Sure, understood perfectly your mod, my rant above was also for newbies not knowing the popper internal subtleties.
But... for 115V poppers... this solution still requires a pump, which is more difficult to source than a switch.

For 230V though, your solution could equate the external motor power source as complexity and cost.
Edited by renatoa on 01/06/2025 8:41 AM
 
Billy Bean
Top  #7 Print Post
Posted on 01/06/2025 9:27 AM
Yes, it still requires a pump. For $27.00 (Canadian) you have an adjustable one on Amazon. That might be a bit more expensive but I can load a bit more beans and there is a 4th advantage that I did not mention yet, I could use the external air pump to empty the roaster after cooling the beans, see image. The flex hose would be disconnected during the roast. I think it is well worth the bit more money and if ever something happens with the air popper, I only buy the same one (used or not) and replace the steel cup with the 3D printed white attachment. I don’t mind your “rant” but I think I deserve a little bit more slack until I am done but I appreciate every feedback/input. Cheers.

infento.design/grinder/8.jpg
Never delay what you can do today....
 
Nilewoods Roaster
Top  #8 Print Post
Posted on 01/06/2025 1:13 PM
Billy, I can see you’re enjoying solving the technical challenges with an air popper.
Have you considered a possible next-step with a flour sifter? If you have a heat gun and an electric drill the other parts are low cost, for a much higher capacity roaster.
Have fun with the journey.
Nilewoods Roaster attached the following images:
img_8344e.jpeg img_8342e.jpeg
Edited by Nilewoods Roaster on 01/06/2025 1:18 PM
 
Billy Bean
Top  #9 Print Post
Posted on 01/06/2025 1:42 PM
Hi Nilewoods, I deliberately have chosen the “straight shooter popper” as it has challenges that I think (hope) I can turn around into something positive.
I don’t need big volume as I live alone and I prefer to roast on a regular base. I think I am on a good run and once finished I will use it to learn better roasting and enjoying my coffee.
I have a completely new design in mind for the future but that is of no use as long as I don’t know the (basic) tricks of roasting.
Yes, I enjoy the challenges, I have lived from my ideas the last 20 years or so (completely different domain), am now (semi) retired and have finally time for my “hobby ideas”.
Never delay what you can do today....
 
Billy Bean
Top  #10 Print Post
Posted on 01/06/2025 7:50 PM
A quick test with the external air pump attached.

I am using a Coleman air bed pump (39 CFM) for the time being until I get my other air pump.

Video explanation: (link below)

1 – In the beginning you see the flexible hose attached to the popper.
2 – Here you see the start-up. The external pump is running on 50% and no movement of the beans (100 gram). Then I start to
popper and you see the beans start to move. I only ran for a short time as the Coleman pump made a very strange noise.
3 – Last piece of the video that I attached the external pump to the voltage regulator that I use with my still (another hobby of
mine)

Tomorrow I will get my air pump, it is 110 CFM and it has its own regulator. 110 CFM is a lot but I will use it in the 50 – 60% range, that will bring down any noise (I hope).

All in all I am pretty happy with this, I was aiming for around 80 gram but with the new air pump I might have higher possibilities although I would have to change something with the chimney.

Edited by Billy Bean on 01/08/2025 3:51 PM
Never delay what you can do today....
 
oldgrumpus
Top  #11 Print Post
Posted on 01/06/2025 11:11 PM
Glad to see you motivated and making good progress. I started also in similar fashion as others of us have. I was not at all encouraged by my efforts with the air popper. I then moved on to an old fire extinguisher over a propane burner that was used for such things as boiling crabs and deep frying turkeys. That too was frustrating. But it looks like you're on a much more positive track so stick with it!
 
Billy Bean
Top  #12 Print Post
Posted on 01/09/2025 9:50 AM
I got my new external air pump yesterday and was very disappointed, very low sound, lots of air but the air did not push the beans. I was ready to send it back to Amazon but then I realized that the problem was maybe not the pump but wat was in front of it. Made a coffee, thought about it and came to the following conclusions and (maybe) solutions.

infento.design/grinder/9.jpg
infento.design/grinder/10.jpg
infento.design/grinder/11.jpg
infento.design/grinder/12.jpg

So….time for a test run.

FASTEN YOUR SEATBELTS, THIS IS GOING TO BE FUN.



So what went wrong? I know for 100% what went wrong. The slots I grinded in the air exit in the bottom of the hopper are very rough and have burrs that are sharp. When I started the roast, I first threw in the beans and one of the beans got stuck in the biggest slot at the bottom. Because it could not move and the heating was on, it became a red-hot ember. And because the ember stayed there, it hindered the other beans going into the tube and they got hot as well and it became a chain reaction. Temperature went up to 350C (662F) before I took action. The smoke in my little test room was worse that the wild fires in California lol. It must be this as, in the dry-run without heating I also got a bean stuck in that slot but I did not think about the consequences in a hot-run. Also, I started the roast with 100% heating, maybe I should start lower and increase in time.

Look at 37 seconds in the timeline, from one second to the other some beans get brown, followed a few seconds later by green beans again.

Was there something positive? I was VERY happy with the outcome of the copper tube launching the beans, that went very well. I am also VERY happy that my (only) popper still works.

What to do now?

- Replace the mesh in the bottom of the hopper.
- Change the lips at the bottom of the tube, I will come back to that later.
- Start the roast with only the external air, no heating, so I can check upfront if it goes well.
- Maybe more external air at the start of the roast.

Dark French roast anyone? Grin

Let me know what you think, maybe I am missing things here.
Edited by Billy Bean on 01/09/2025 10:11 AM
Never delay what you can do today....
 
renatoa
Top  #13 Print Post
Posted on 01/09/2025 12:34 PM
Welcome to the Verti(cal)flow https://homeroast...post_72667
 
HarryDog
Top  #14 Print Post
Posted on 01/09/2025 12:43 PM
I never used a mesh popper but I did try a few, the one I liked was the AIcook.BMH-1202A it has drilled holes. I used a 24v DC power supply and this would allow me to float about twice the amount of beans that it would at stock voltage as I think it ran at 18v? So it might shorten the life of the motor a bit. I then upgraded to a Canadian tire Mastercraft workbench blower that allowed me to roast 1 pound at a time. Never thought it would do it but it did roast that much very well once I insulated the glass tube I was using. I made a little control box as I did test a few different poppers just for fun. If changing the base I would look at this image.
renatoa wrote:
HarryDog attached the following images:
aicookbmh.jpg controlbox_1.jpg
 
Billy Bean
Top  #15 Print Post
Posted on 01/09/2025 3:56 PM

Quote

HarryDog wrote:

I never used a mesh popper but I did try a few, the one I liked was the AIcook.BMH-1202A it has drilled holes. I used a 24v DC power supply and this would allow me to float about twice the amount of beans that it would at stock voltage as I think it ran at 18v? So it might shorten the life of the motor a bit. I then upgraded to a Canadian tire Mastercraft workbench blower that allowed me to roast 1 pound at a time. Never thought it would do it but it did roast that much very well once I insulated the glass tube I was using. I made a little control box as I did test a few different poppers just for fun. If changing the base I would look at this image.
renatoa wrote:


Hi HarryDog, for now I stick to a small design and make this one to learn roasting. Eventually I have a completely different design in mind but I need to go step by step, that’s how I learn, with trial and error. Actually, despite the bad impression, I found my test pretty successful, I learned exactly what was good and bad. The control box you saw in the video, I built that one for my still. Don’t you just love that voltage regulator? Cheers.
Never delay what you can do today....
 
HarryDog
Top  #16 Print Post
Posted on 01/09/2025 4:04 PM
Did you check out that pic Renatoa wrote, click on that link to see the asymmetric base plate, might be something you want to try in this design?
 
Billy Bean
Top  #17 Print Post
Posted on 01/09/2025 4:20 PM

Quote

HarryDog wrote:

Did you check out that pic Renatoa wrote, click on that link to see the asymmetric base plate, might be something you want to try in this design?


Yes I saw it but could not figure out how it works. Update: I saw the video and I think it works like this: the beans are forged down and fall because of their weight but the chaff is soo light that it will be sucked up. Clever
Edited by Billy Bean on 01/09/2025 4:27 PM
Never delay what you can do today....
 
renatoa
Top  #18 Print Post
Posted on 01/10/2025 6:09 AM
Actually this was the way how all the fluid bed story started... the original Sivetz machine used and still use the drop/leaf format for the roast chamber.
A quick search for Sivetz roasters will reveal you more than I can write here.
 
Billy Bean
Top  #19 Print Post
Posted on 01/10/2025 7:28 AM

Quote

renatoa wrote:

Actually this was the way how all the fluid bed story started... the original Sivetz machine used and still use the drop/leaf format for the roast chamber.
A quick search for Sivetz roasters will reveal you more than I can write here.


Thank you for pointing me out to Sivetz roasters, that is very interesting indeed.
Never delay what you can do today....
 
Billy Bean
Top  #20 Print Post
Posted on 01/10/2025 5:49 PM
Made some changes as I am not giving up (yet…). Changed the mesh in the bottom of the popper, very happy with that, I have like 30% more air (it’s a guess).

infento.design/grinder/13.jpg

Did a new test (80 gram) with that and had no problems. It also looks is I have much more heat now. I experimented a bit with temperatures and I went to 480F without any problems and I could adjust temperatures up and down. The inner copper tube went sideways a bit during the roast and the little hood on top did not work well, had it in not a good position so about 20% of the beans flew out the chimney. But at least I have some beans now for my fresh morning coffee. The 480F was not the maximum but I did not want to go any higher. I think I will ad more external air with the next test to compensate for the too much heat. (and fix a better hoodGrin)

Never delay what you can do today....
 
Billy Bean
Top  #21 Print Post
Posted on 01/10/2025 6:56 PM
Some quick testing(3x), went very well, had control over the temperature all the way.
It looks as if the roast is not even but it is the reflection of the light above.

infento.design/grinder/14.jpg
Never delay what you can do today....
 
Billy Bean
Top  #22 Print Post
Posted on 01/12/2025 1:09 PM
Hello all, an update on lessons learned from the previous tests.

infento.design/grinder/15.jpg

infento.design/grinder/16.jpg

infento.design/grinder/17.jpg

infento.design/grinder/18.jpg

infento.design/grinder/19.jpg

I hope to do a small run this evening but not sure as I get visitors. Cheers.
Never delay what you can do today....
 
Billy Bean
Top  #23 Print Post
Posted on 01/13/2025 5:13 AM
Did a small test yesterday evening very late (without the center copper pipe) but it was a short one as we had a power outage after 5.5 minutes but here are my 2 cents.
- The chaff collector worked very well.

- The 1” pipe is a bottleneck in the outgoing (and internal) airspeed, I could only load 50
grams of beans to still let the beans “dance”.
- This means I have to get rid of the 1” exit pipe, so bye-bye present chaff collector.

I had put some already roasted beans in the batch (the black ones) to see if I could see the movement in the hopper.

Plan of attack:

- Bring back the center pipe so I can load more beans, I am aiming for around 80 grams.
- Another chaff separator, if possible, I will follow the advice of renatoa and and do an attempt to come up with something like Sivetz roasters, but my space in the chimney is very limited.

If anyone has a good suggestion, please don’t hold back.

Never delay what you can do today....
 
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