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Building a roaster
Henrikp
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Posted on 01/09/2021 6:00 AM
Does anyone have link or drawings for building a roaster ?.
 
renatoa
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Posted on 01/09/2021 7:52 AM
Type, capacity, heat source ?
 
Henrikp
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Posted on 01/09/2021 8:53 AM
Type i am in doubt, about 600 grams in capacity, electrical heart source
 
renatoa
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Posted on 01/09/2021 9:05 AM
A turbo oven lid based setup is the simplest and most effective solution you can approach.
Check for KKTO/SCTO/"turbo oven coffee roasting" acronyms.
 
jkoll42
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Posted on 01/09/2021 3:25 PM
Heat Gun Bread Machine would be in your capacity range as well
-Jon
Honey badger 1k, Bunn LPG-2E, Technivorm, Cimbali Max Hybrid, Vibiemme Double Domo V3
 
renatoa
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Posted on 01/10/2021 3:00 AM
Average roasted coffee density is 432 grams per liter, so you will need a larger model, at least 1.5 l capacity to fit the beans when level, significantly more if you don't want them spill when agitated.
The 1:6 rule used for drums would say you need a 3.6 l roasting chamber.
 
jkoll42
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Posted on 01/10/2021 6:28 AM

Quote

renatoa wrote:

Average roasted coffee density is 432 grams per liter, so you will need a larger model, at least 1.5 l capacity to fit the beans when level, significantly more if you don't want them spill when agitated.
The 1:6 rule used for drums would say you need a 3.6 l roasting chamber.


If you are talking about a HGBM a standard (in the states they are called 2 pound models) bread machine has more than enough enough capacity for that bean load with agitation. I roasted for years with this setup - it's still retired in my basement.
-Jon
Honey badger 1k, Bunn LPG-2E, Technivorm, Cimbali Max Hybrid, Vibiemme Double Domo V3
 
renatoa
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Posted on 01/10/2021 7:38 AM
The large machine you wrote above seems to have 3 litres, indeed it is good for 500 grams of greens:
https://www.doves...d-machines

However, I feel the need to clarify this size requirement... there are also thermal issues beyond canister capacity.
The same reasoning that led to the 1:6 rule apply here, and for all roast machines as well.
To perform the roast, coffee beans needs a given energy to be transferred from hot air. The energy stored in air is a factor of volume and temperature, (and other physics constants we can't change).
If you reduce the air volume, the only way to raise the beans temperature at right rate, is to raise air temperature. But we have the 270 C limit, where cellulose melt, and bean matrix suffer damages.
I seen a lot of people claiming they roast a pound in the small model machine, the 800 grams model, that is predominant here in Europe, omitting the little detail they dial their hotgun well above 300-330 C, which is torture, not roasting, imo.

If needed, another confirmation of the above comes from a commercial roaster: Gene glass has 1.5 l volume, why not load it more than 250g ? Rule 1:6 Grin
 
CupOfJoe
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Posted on 11/02/2021 2:08 AM
Needing some guidance for the drum dimensions of a 2lb gas drum roaster. I found the 1:6 rule in the thread. Is there a rule for diameter to lenght?
 
renatoa
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Posted on 11/02/2021 2:08 AM
Close to cubic, i.e. diameter close to the length, but not mandatory.
A typical 1 kg drum is 8" by 8" (20x20 cm)
However there are a lot of commercial machines examples having longer roast chambers, like Gene or Behmor.
Depends of the tube size you can supply.
Edited by renatoa on 11/02/2021 4:42 AM
 
Koffee Kosmo
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Posted on 11/04/2021 6:00 PM

Quote

renatoa wrote:

A turbo oven lid based setup is the simplest and most effective solution you can approach.
Check for KKTO/SCTO/"turbo oven coffee roasting" acronyms.


It’s an easy build and assembly
It will take approximately 1 hour once you have all the parts on hand

With the mods I have made the roaster is capable to roast 1 kg and I still stand by the claim that the sweet spot is 650 to 750 grams

KK
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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BernardJ87
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Posted on 11/11/2021 11:35 PM
Good information.
 
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