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Infrared Halogen BreadMaker Roaster
scarter11
I thought I'd start a thread to document the progress on my Halogen-Bread maker roaster.

I borrowed ideas from a thread over at CoffeeSnobs, as well as BoyntonStu's unassisted BM thread.

http://coffeesnob...1196336104

http://forum.home...rowstart=0

I found a Regal Breadmaker at Goodwill for $12, that looked like it had never been used. Probably a gift that never saw any use. It was time to put it to a better use. Re-wiring it was easy; wires for the motor, heater and sensors went straight back to the logic board, and will clearly labeled. I removed everything but the motor / capacitor and the heater. The heater has a switch on it so I can turn it on and off. After testing the heat output of the heater by itself, I definitely was going to need more power.

I ordered a heat gun from Harbor Freight, but after reading the CS thread, thought I'd like the quieter Halogen heat source. If anyone is looking for a heat gun, PM me. ;)

I picked up a 500 Watt Halogen work light from Lowes for $10, and placed it on the top of the BM. Without beans, it would heat up fairly fast, reaching 300f in 2.5 minutes. I only had about 1.5 cups of some Sumatra Mendheling from Sweet Marias. I preheated to 300 and dropped the beans. First crack happened at 8 minutes, and second started around 11:30.

I had to wait a week before my SM 4 pound sample, but was ready to see how the roaster handled a larger batch. My next roast was a pound of Guatemala Fraijanes - Finca Agua Tibia. This roast didn't go nearly as well. The roaster is definitely under-powered. It took 25 minutes to reach second.

I'm planning to mount a second 500 watt bulb in the work light. One will be on a switch, and the second on a 600 watt dimmer. This will give me full control from 0 to 1000 watts. Hopefully this, along with the internal heater from the breadmaker, will give me the power I need to roast a pound or more at a time.
 
PeteH
I'm anxious to hear how it works out with two 500w bulbs, should give it quite a boost. As you probably know, some bread machines have a long flat bread pan that doesn't work as well with a HG but I wonder if it wouldn't work better with a work light. It's about the same size and would let more heat from the light get to the beans as the area exposed to the light would be larger..
Pete
 
scarter11
While doing some research on using infra-red heat to roast coffee, I found this interesting article:

http://www.asic-c...16_047.pdf
(The Association For Science and Information on Coffee)
 
allenb

Quote

scarter11 wrote:
While doing some research on using infra-red heat to roast coffee, I found this interesting article:

http://www.asic-c...16_047.pdf
(The Association For Science and Information on Coffee)


Japan and Korea have put in quite a bit of research into infrared roasting. The Unimax was interesting but had no control so you'd blow from 1C to finish without a pause most of the time.

I've done my share of experimentation with infrared radiant as a primary heat source and you can achieve excellent results.

Some things to consider when designing a radiant roaster.

Larger surface areas allow lower wattage elements and is easier on the beans. Unlike hot air, infrared can't travel around corners.

Keep at least 3+ inches between element and bean mass.

If possible, use more than one wavelength. The work lights are very short wavelength. If you add a medium or long wavelength in the mix it seems to get more done with less overall wattage. Some have claimed that at start of roast, short wavelength is most efficient and after browning the longer wavelength is a better efficiency.

There is an exponential decrease in wattage needed as beans become darker. With my one pounder, I"ll start out at 900 watts and by halfway into 1C I'll be at 250 watts to maintain a slow finish. If I couldn't dial it down below 500 I'd end up with a final phase of less than 2 min.

PID control is tricky. I've had good luck with tight control up to 1C but after that I have to take over manually. One setup of proportional and integral settings seem to work good for start to 1C but allow too much slop afterward without resetting them. I'm not fast enough to change them on the fly.

Good luck with the project!

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
scarter11
What device produces medium or long wavelength IR?
 
allenb

Quote

scarter11 wrote:
What device produces medium or long wavelength IR?


An example of something producing a medium wavelength IR would be a nichrome wire coiled element inside a quartz tube commonly seen in toaster ovens and any tubular metal element found on household stoves/ovens. (medium to bright orange).

Long wavelength will be barely visible color to no color as in the salamander elements.

http://www.infrar...eramic.htm

One problem with the long wavelength elements is they take up more surface area for a given wattage. It might be better to limit the design to medium and short wavelength if space is an issue.
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
scarter11
Would that include the bread maker's internal element that I'm already using? Or would the bread pan be blocking the IR waves and only heat by contact?
Edited by scarter11 on 07/16/2010 5:52 PM
 
allenb

Quote

scarter11 wrote:
Would that include the bread maker's internal element that I'm already using?


I'm assuming the element your referring to heats the bread pan and does not radiate IR directly onto the coffee?
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
scarter11
That is correct. So I assume the element would need to be moved to the lid, a place with an unobstucted path to the beans. That brings up another question. I wonder how well IR radiation penetrates the bean mass?
 
allenb
Medium wavelength IR is just light at a longer wavelength.
Light travels in straight lines.

While IR will penetrate somewhat, depending on the material, it won't go through one bean and into the next. It will hit what it can see, line of sight.

That's why you want to maximize bean surface area exposed to the IR and keep them circulating well. The bread maker will do fine as long as you don't have a disproportionately deep bed depth compared to cross section.

Whether the on-board element will suffice for IR purposes is hard to tell.
Whats it's wattage, will it fit in the space around the halogen? If not, there's other options. On the other hand, you might put it together with the halogen and outside the pan heat and achieve excellent results. Sometimes it's nice to build-in all that you want to try (up to a point) so you can experiment.

No matter how you decide to build this it will be a fun project and I'm sure you will end up with some great tasting coffee!

Happy building,

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
John Despres
I'm using 2000w for my 1 kilo drum roaster and they are working fine.
Here's the thread http://forum.home...post_19606

Good agitation is a must with halogen.
Allen has nailed it - the IR will not travel through the beans, however the heat will, but agitate, agitate, agitate.

Great thread!

John
Respect the bean.
John Despres
Fresh Roast 8, Gene Cafe, JYTT 1k, Quest M3, Mazzer Mini, Technivorm, various size presses and many more brewers.
 
scarter11
I'll finish the install of the second halogen bulb tonight. Maybe have time to give it a go.
 
scarter11
I think it is about time to update this thread. My Halogen Breadmaker roaster has now morphed into a Halogen - Heat Gun - Breadmaker roaster. Grin

I wanted more control over the roast profile, and the added heat gun during the ramp from 300f to first crack really helps. So far I have roasted only 1 pound batches, but am confident I can go bigger now.

Here are some pics.
scarter11 attached the following image:
imag0052.jpg
 
scarter11
Closeup of dual halogen and heat gun. I formed a heat deflector out of some of the aluminum reflective material.
scarter11 attached the following image:
imag0053.jpg
 
scarter11
And here is my latest batch.

Preheat to 200
Medium heat to 300 in about 5 minutes
High heat to first crack at 9.47 minutes @ 407f
Low heat to the end of roast 12.12 minutes and 440f.

It is hard to get a representative pic without the flash affecting the darkness, especially with my Droid Incredible.
scarter11 attached the following image:
imag0049.jpg
 
scarter11
Last but not least, A couple pics of my $4.00 cooler. It is very effective at cooling to touch in under a minute.
scarter11 attached the following image:
imag0050.jpg
 
scarter11
The only cost I had was this, at $3.99 from Goodwill. The vac was an old one that we replaced.
scarter11 attached the following image:
imag0051.jpg
 
seedlings
Well done! I love the ingenuity and resourcefulness!

CHAD
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
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