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Ideal Roasting Chamber Dimensions?
nixda
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Posted on 11/07/2013 2:14 PM
I was wondering if there are any general rules regarding the dimensions of a roasting chamber.

I am in the (slow) process of building my roaster that is supposed to accommodate 1 lb of green coffee. Heat will be provided by hot air, perhaps augmented with direct heating of the vessel. The vessel is supposed to be stationary with an agitator moving the beans (like a bread-machine-type roaster).

Any thoughts about what the perfect diameter would be? I am looking for something like diameter versus bean weight, or unit area versus bean weight, or the like.

Many thanks in advance!
 
oldgearhead
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Posted on 11/07/2013 2:26 PM
Sounds like a large Zach & Dani's (Nesco) with an auger.
With my fluid bed I roast one pound using a 3.25" (id) x 14.0"
glass tube. All height is needed for cooling, about half for roasting.

Are you really planning to use an auger?
No oil on my beans...
 
JETROASTER
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Posted on 11/07/2013 2:45 PM
Here's a little something from the downloads section. It's only useful for fluid-bed design. Sorry, may not be applicable.

http://forum.home...nload_id=1

You'll need to be signed in to download. -Cheers
Edited by JETROASTER on 11/07/2013 3:05 PM
 
nixda
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Posted on 11/07/2013 3:16 PM
I wasn't clear: it's not going to be a fluid-bed roaster, but a bread machine/heat gun type roaster. I will not use an auger; just a plain paddle of some sort.
 
Koffee Kosmo
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Posted on 11/07/2013 3:26 PM

Quote

nixda wrote:

I wasn't clear: it's not going to be a fluid-bed roaster, but a bread machine/heat gun type roaster. I will not use an auger; just a plain paddle of some sort.


The chamber size of the bread machine is ideal when used in conjunction with a heat gun

KK
I home roast and I like it. Designer of the KKTO
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https://docs.goog...lide=id.i0
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Bezzera Strega, Mazzer Robur Grinder, Pullman Tamper Convex,
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Lawnmowerman
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Posted on 11/07/2013 4:05 PM
I have all the vessels yoy need. I was hopng tp build a sinilar project. The bean vessel is 7in round 8 inch tall witj a glass lid. It fits inside anothet inside anothet. The plan is to bolt the largest vessel to a breadmaker base, incirporate a skillet heater, one layerof insulation then one more pot all bolted together. Center bean container removes like a b m. Top it all off with pizza pan for a lid, some kind of viewing glass, run the heatgun into that somehow. Well you can see i got carried away. Might need to use a vacuum bean removal for this. This whole scheme allows for a layer of hot air directly surrounding the bean canister. When i get time. I like to think of this as how a breadmaker would have been built if it had been intended to roast coffee.
Bad coffee prevails when good coffee roasters stand by and do nothing.
 
Lawnmowerman
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Posted on 11/07/2013 4:13 PM
Lets see if i can get a pic posted
Lawnmowerman attached the following image:
cam00406-1.jpg
Bad coffee prevails when good coffee roasters stand by and do nothing.
 
nixda
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Posted on 11/07/2013 5:23 PM

Quote

Lawnmowerman wrote:

I have all the vessels yoy need. I was hopng tp build a sinilar project. The bean vessel is 7in round 8 inch tall witj a glass lid. It fits inside anothet inside anothet. The plan is to bolt the largest vessel to a breadmaker base, incirporate a skillet heater, one layerof insulation then one more pot all bolted together. Center bean container removes like a b m. Top it all off with pizza pan for a lid, some kind of viewing glass, run the heatgun into that somehow. Well you can see i got carried away. Might need to use a vacuum bean removal for this. This whole scheme allows for a layer of hot air directly surrounding the bean canister. When i get time. I like to think of this as how a breadmaker would have been built if it had been intended to roast coffee.


That is almost precisely like what I have in mind. I was planning on using bain marie pots (http://www.webstaurantstore.com/3-1-2-qt-bain-marie-pot/92278730.html), a smaller one nesting in a larger one. Hence my question about the right size. These pots are tall enough to accommodate a hot-air entry port on the side, instead of from the top.

I was thinking of putting insulating material between the two pots and perhaps even wrapping some resistance heating wire around the inner one, but I am afraid to exceed 15 amp. One of the design goals is to be able to run the machine off of a normal circuit.

The top would use the lid for the outer pot with a large hole cut into it, a silicone gasket around the edge of the hole, and a piece of Pyrex glass on top as a viewing window. There would also be a gasket on the underside of the lid that seals against the inner pot, i.e., the roasting chamber.

The motor might be interesting... I have a defunct blender, but the motor works fine. Of course, it would be way too fast, but with the proper gear ratio, or a belt going to a larger wheel that then drives the agitator, it might work. It' certainly strong enough to move a pound of beans. But again, it might trip the circuit when all is said and done.

I was also thinking of a third vessel to enclose everything, but that will depend on the motor. In any case, it's all doable using bain marie pots, and one wouldn't even have to reduce their height to make it all fit.

It's fun to think about all this. I hope I'll get around actually doing it...
 
Koffee Kosmo
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Posted on 11/07/2013 9:23 PM
The KKTO design can be used with a heat gun as a heat source
So if you are not going to utilise a bread maker machine then look at a KKTO design

See this thread - http://www.bestca...at-source/

And for anyone converting from a Turbo Oven see this thread - http://www.bestca...o-roaster/

KK
Edited by JackH on 11/08/2013 6:06 AM
I home roast and I like it. Designer of the KKTO
Roaster Build information
https://homeroast...ad_id=1142

https://docs.goog...lide=id.i0
Blog - http://koffeekosm...gspot.com/

Bezzera Strega, Mazzer Robur Grinder, Pullman Tamper Convex,
(KKTO) Turbo Oven Home Roaster.
 
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