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CharcoalRoaster
11/04/2019 1:58 AM
+1 snwcmpr

snwcmpr
11/03/2019 2:16 AM
Can we make the shoutbox UNAVAILABLE until a member has a certain number of posts?

allenb
11/01/2019 2:20 AM
Funopt, please post in the gas and electric heat sources forum

Funopt
10/30/2019 5:17 AM
Can someone help me for using forced propane burner as my heating element. I rather want to use lpg than electric. Do you think it would work

snwcmpr
10/22/2019 5:31 AM
Thanks to you all....... I was not sleeping ... I stayed awake worried about it all. :)

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first DIY-Build 0,5-1kg
DeepB
Hello,

I love drinking espresso, and am interested in building a DIY home-roaster.

I have never roasted coffee before. However I do not want to buy small/simple machines that I already know I will replace anyway.

What I am looking for:
1) reproducable good results
2) Batch size 0,5-1kg
3) Easy and if possible cheap to build.

Other Considerations:
*) I do not care if electroic or gas
*) situated in Europe if that changes anything (avilability of parts)
*) not decided on a system (drum/direct flame...)
*) I can do (very!) basic welding, and am generally happy with any material
*) handheld plasma-cutter available, though only up to about 6-8mm strength of material
*) I would prefer the roaster to be software controllable. I can do basic programming.
*) currently using about 15 kg coffee/year, when roasting myself this will probably go up to ~30kg/year

looking forward to your input
thanks
Daniel
 
renatoa
For similar goal I have already voted for a machine using hot air + IR direct to beans, based on a variation of the popular turbo oven lid.
Much simpler and cheaper to build than a drum, and easier to control, less troubles with airflow control and overthinking.
No cutting or welding required, just drilling.
First iterations can be operated without any electronics, just the lid power controls and timer, with very good results.
When I roasted for my office last year, the average was three roasts of 2kg every weekend, so 8 kg monthly.
 
DeepB
That does sound interesting.

Are there any examples of a build like that here? Unfortunately I found none searching...
 
renatoa
Check the whole section devoted to such builds, noticed "Turbo Oven" in the main forum page ?
Try searching for KKTO, the basic concept that inspired a lot of people build their own variations.

Some people even approach professional roasting with two such units, like this guy:
https://sites.goo.../peter4jc/

I dream to build such setup looking as a DJ mixing unit, with two turntables Grin
Edited by renatoa on 09/24/2019 11:17 PM
 
DeepB
Oh, I found the Turbo-Oven section. I was talking about the IR-version.
 
renatoa
If using the FIR version of the lid, from sunpetown...
Or simply remove the halogen protection tin plate, will add a lot of IR.
Or replace the halogen of a regular lid with a carbon fiber tube like this, probably very close to sunpetown's:
https://www.aliex...83449.html

Personally experimented with #2 and #3 from the options above, I didn't noticed a significant change in roasts done with carbon tube, so actually I am still on halogen, to better see the roast progress, carbon produce too little and orange hue light, not useful to evaluate beans color.
 
marcov
renatoa wrote:

For similar goal I have already voted for a machine using hot air + IR direct to beans, based on a variation of the popular turbo oven lid.
Much simpler and cheaper to build than a drum, and easier to control, less troubles with airflow control and overthinking.
No cutting or welding required, just drilling.
First iterations can be operated without any electronics, just the lid power controls and timer, with very good results.
When I roasted for my office last year, the average was three roasts of 2kg every weekend, so 8 kg monthly.


Is there some build / proof of concept of a roaster using the turbo oven lid as heating element and fluid bed for beans agitation?
 
renatoa
Someone could think to a method of recirculating hot air taken from the oven, passed through a high temperature blower, and back into the oven, still hot enough, just for beans tumbling, but...
Why fluid bed for agitation?
What are the virtues of levitating instead mechanical agitation ?
 
marcov
From what I see in the tradition turbo oven roasters, the beans are mixed at a low frequency, and they does not seem to mix in a homogeneous way. So you can get unevenness, scorching, or tipping.

I was just wondering if there could be a better way to agitate beans that would be easy to implement, e.g. not requiring something like a rotating drum.
Maybe a vibrating platform?Grin
 
renatoa
I don't see the reason for scorching and tipping, if heat is well managed.
The metal parts in a turbo oven setup have the same temperature as the beans, unlike in a drum where the drum is at least 50C hotter than the environment (air inside). This is the main reason for such roast defects.

If the agitator arms are well done, and tuned with rotation speed, the is no unevenness also. Rotation speed for most TO setups is in the same ballpark as the drum roasters, about 60 RPM.
Floating in air does not guarantee evenness, if the airflow is only for agitation, not for heat transfer too.
Conversely, my quest for better roasting led me to turbo oven because attempts for a good agitation in various FB experimented in early stage of roasting hobby all failed. At least for 500 grams target.

A better way? Sure it is , but nobody tested it because required some equipment and skills you listed as available in the OP: tin cut and welding.
Check "Probat centrifugal roaster" principle and will understand better what I mean... Grin and how wonderful a turbo oven lid can provide heat for such concept... with a difference though... the airflow direction will be reversed, from the walls to the center.
Edited by renatoa on 09/25/2019 6:26 AM
 
DeepB
When using IR-Heating, how can you measure bean temperature?

thanks
Daniel
 
renatoa
With a probe fully inserted into bean bed, to minimize hot air influence.
IR won't affect too much a stainless steel probe, it is reflective, but hot air (environment) still influence the reading.
Seems I am having accurate enough measurements, TP about 90 C at 1 minute, DE in the 5 min ballpark at 145-150 C, FC in the 195-200 C range.

A note, when roasting using IR heat quota bigger than convective, knowing BT is mandatory, else you mostly roast based on senses... That's because ET don't tell so much as in pure hot air roasting, average ET is significantly lower, under 250 C at FC.
Actually, in such machines hot air is a byproduct of producing IR, you can't produce IR without heat... convection, i.e. hot air, contributes mostly in drying phase, when beans are lighter color and don't absorb much IR, but in final phases of browning this equation changes.
 
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