Roaster has no Airflow control.

Feb 22, 2024
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South Africa
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Good day to all.
I started roasting last year and am using a 5kg cast iron double wall drum roaster with LPG gas as a heat source. so far I have been getting some very nice roasts when I go for anything in the light to medium ranges. although i am struggling to prevent a smokey flavor from seeping into the coffee when I reach second crack for my medium dark roast( I drop just before/on second crack happening, to the point that it starts cracking as i drop) I aim for a 25% development ratio for the MD roast.

My big problem is that I have no control over cyclone fan speed or the size of the pipe. I can open a sliding tube on the back end of the roaster but getting there is an immense hassle and would only make the suction force of the cyclone even less. I have checked my exhaust tubing recently and there is a bit of caking inside, I am looking into getting tools to help me clean it as nothing I have atm. will work.

Any thoughts would be appreciated.

I drop at 230'C, First Crack Happening around 207-214'C depending on the day's weather, and Drop Out around 230 again.

Coffee is Brazilian Santos, SCA Grade 81. Personally I would prefer roasting it around 22-24% development at a medium roast level but Clients want "Dark Raost".

Development % based on time from first crack till end of roast. I am starting to work on incorporating smell and colour more into how I roast, but the DTR has been helpfull with staying relatively consistent.
 

wmark

Member
Nov 12, 2008
494
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Canada
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1. Clean your bleedin' exhaust pipes
2. Figure out some way to increase airflow. Can we assume that you have some sort of domestically built machine ?
 
Feb 22, 2024
3
0
South Africa
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1. Clean your bleedin' exhaust pipes
2. Figure out some way to increase airflow. Can we assume that you have some sort of domestically built machine ?
1. Thank you wmark. I intend to do so, just struggling to find equipment that I can use for said purpose.

2. It is "domestically" built in a sense yes, made by a company in country. Double gas burners. Delta PID for controlling drum speed and turning everything on/off.
Just thinking out loud, but have you considered adding a motor speed control? Maybe something like this would work in your specific situation?
https://a.co/d/3zFsZNV
I actually haven't thought of using an external add on no. I was wondering if it might be possible to add another motor controller from Delta to our current system but due to lack of communication capability withthe manufacturers of our roaster I am very much left in the dark to find my own way around things. 💀😄
 

wmark

Member
Nov 12, 2008
494
7
Canada
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How hard are you looking ? Try a chisel.

What ? You can control drum speed and not air flow ? Incredible
If you know how to wire it in, get a variable speed motor to control the fan. Can advise you as to the motor controls
 
Feb 22, 2024
3
0
South Africa
Visit site
How hard are you looking ? Try a chisel.

What ? You can control drum speed and not air flow ? Incredible
If you know how to wire it in, get a variable speed motor to control the fan. Can advise you as to the motor controls
I managed to find a flue brush that is working wonders to get the buildup out. Have not noticed an improvement in airflow per se but at least I can keep the roaster cleaner now.

I know, I find it crazy that there is no airflow control options built into the roaster. I will do some research on control for our fan. I do not know how to do the wiring process but have access to a local handyman that should be able to help.

There's a lot of things that I want to implement in our process at the moment and I have to gradually bring my problems and suggestions to the owner attention so as to not come over overbearing/needy. Of course getting our machine "Upgraded" and integrated correctly as well as figuring out maintenance scheduling is on the top of that list at the moment.
 
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