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JackH
OfflineAdmin
· 08/06/2020 3:33 PM
Allenb, how are you doing?

Oneal
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· 08/05/2020 1:08 PM
Is anyone roasting on a Coffee Tech FZ 94? Using Artisan. Need help. thumbdown

mtbizzle
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· 08/03/2020 11:26 AM
There is (or was? Grin ) a gesha at sweet marias...

snwcmpr
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· 07/25/2020 12:31 PM
I ran out of Ethiopian Gesha.

snwcmpr
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· 07/25/2020 12:31 PM
it is ok. I do not remember. I think it was a callout to the spam shout.

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Heating Element for DIY drum roaster?
CyrusF
Hello all! I've been stalking this forum ever since the idea of this project was born, but I haven't found exactly what I'm looking for. Here's my main question: What kind of heating element do I need to be looking for for a 1kg roaster? I was looking at ceramic elements, but I'm really not sure what is standard. The Behmor countertop unit uses quartz, but I haven't found those very readily available online with detailed product specs. (They're usually replacement parts for other devices!) There may be more to this question than I realize, but I appreciate the help!
 
allenb
Hi Cyrus and welcome to HRO!

I would design around the classic solid drum, beneath the drum heated, perforated back drum roaster with typical exhaust through the fill funnel. They are unfortunately difficult to utilize an open nichrome type heating element and is better to utilize tubular heating elements. There are companies who will custom bend a tubular of your design and you can spec out the mounting plate and type of electrical connections. Go for around 3 to 4 KW and use a watt density that would allow full power to it in still air without going over the max sheath temperature.

You mentioned the Behmor. The Behmor is a radiant to bean roaster and is much more of a challenge than a traditional solid drum roaster due to the difficulty in controlling the infrared output well enough to move the beans through preferred RoR profiles.

Have fun and shoot us photos during the build!
Edited by allenb on 07/11/2020 6:49 PM
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
pjvdl

Quote

CyrusF wrote:

Hello all! I've been stalking this forum ever since the idea of this project was born, but I haven't found exactly what I'm looking for. Here's my main question: What kind of heating element do I need to be looking for for a 1kg roaster? I was looking at ceramic elements, but I'm really not sure what is standard. The Behmor countertop unit uses quartz, but I haven't found those very readily available online with detailed product specs. (They're usually replacement parts for other devices!) There may be more to this question than I realize, but I appreciate the help!


Ha. I am facing this exact challenge at the moment with my DIY drum roaster! I had planned to use nichrome, but it is proving far more challenging than I expected.

I have a thread going with many good suggestions, but the problem is unsolved as yet ...
-- Paul

ECM Rocket espresso
Eureka Mignon grinder
500g BBQ rotisserie roaster
1kg drum roaster (under construction)
 
allenb

Quote

Ha. I am facing this exact challenge at the moment with my DIY drum roaster! I had planned to use nichrome, but it is proving far more challenging than I expected.

I have a thread going with many good suggestions, but the problem is unsolved as yet ...


You need to understand that you're looking at two very different modes of heating a drum roaster. On the one hand, what you are doing now is heating a convection air stream with a nichrome wire heater which is the correct way to go for convection heaters. The other, which I had suggested to Cyrus is to heat the underside of the drum in free air via tubular elements which does not have to have forced convection air to keep from overheating the tubular elements. One obviously will want to pull air across the tubular elements as a natural course of pulling exhaust through the drum which pulls ambient air across the tubulars and up across the drum and in through the rear drum opening and then across the coffee and out.
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
CyrusF

Quote

allenb wrote:

Hi Cyrus and welcome to HRO!

I would design around the classic solid drum, beneath the drum heated, perforated back drum roaster with typical exhaust through the fill funnel. They are unfortunately difficult to utilize an open nichrome type heating element and is better to utilize tubular heating elements. There are companies who will custom bend a tubular of your design and you can spec out the mounting plate and type of electrical connections. Go for around 3 to 4 KW and use a watt density that would allow full power to it in still air without going over the max sheath temperature.

You mentioned the Behmor. The Behmor is a radiant to bean roaster and is much more of a challenge than a traditional solid drum roaster due to the difficulty in controlling the infrared output well enough to move the beans through preferred RoR profiles.

Have fun and shoot us photos during the build!


Thanks for the info! I just ordered some components today, and will continue to update as the project progresses! Wish me luck!
 
pjvdl

Quote

allenb wrote:

Quote

Ha. I am facing this exact challenge at the moment with my DIY drum roaster! I had planned to use nichrome, but it is proving far more challenging than I expected.

I have a thread going with many good suggestions, but the problem is unsolved as yet ...


You need to understand that you're looking at two very different modes of heating a drum roaster. On the one hand, what you are doing now is heating a convection air stream with a nichrome wire heater which is the correct way to go for convection heaters. The other, which I had suggested to Cyrus is to heat the underside of the drum in free air via tubular elements which does not have to have forced convection air to keep from overheating the tubular elements. One obviously will want to pull air across the tubular elements as a natural course of pulling exhaust through the drum which pulls ambient air across the tubulars and up across the drum and in through the rear drum opening and then across the coffee and out.


Thanks for the clarification. Yes, I understand. I don't want to hijack Cyrus's thread, so might be better to respond in the other thread I started, but I had hoped to use nichrome to provide a blend of convective and radiant on the drum. Unfortunately my testing with nichrome is showing this is probably not practical with the forced air requirements of the nichrome. Might need to look at tubular elements or gas heating if I wnat more radiant on the drum. I am also considering infrared halogen elements to heat the drum (not directly on the beans).

Do you have a tubular element that you would recommend? I am also wondering how best to control a tubular element using a TC4/Adruino combination. . Do you know if slow PWM still works, or do I need to look at ICC or phase angle control?
-- Paul

ECM Rocket espresso
Eureka Mignon grinder
500g BBQ rotisserie roaster
1kg drum roaster (under construction)
 
allenb
pjvdl
I'll take a stab at your question in your other thread
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
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