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Flour sifter agitators stuck on beans
mtbizzle

Quote

Very strange power needs you have...


Forgot to mention, thermostat is in place in the Poppery II. Another user pointed this out.

May need to remove thermostat, and wire through my fan speed controller. Some concern that it may not get hot enough w/o becoming unsafely hot, but I can't know until I test it I suppose.

I would try test batches w/ 100g of natural beans I have, start power low, perhaps 50-60%, and try to observe for roast landmark timings... Ideally being able to adjust until I get decent timings on the roast landmarks.

Any safety tips for using a popper w/o thermostat? Warning signs to observe for? Grin Fire blanket will be nearby smoking
Roast: Kaldi wide, SR800 + projects
Grind: Lab sweet, Bentwood, giota w/ MP burrs, Commandante
Pull: Decent, La Pavoni, Elektra Microcasa a Leva, Faemina anno 60, Kim Express
 
renatoa
If thermostat is in place, it should trip at 180 C degrees, at least so is the models I know here in Europe. Seems to be related to popcorn charring.
This is the reason thermostat should be bypassed, to allow temperature rise in the 230-250 C degrees ballpark, needed for the right coffee roasting process.
There is another safety measure, a thermal fuse, usually having 270 C as melting point.

As initial tuning, I would try various power levels with the popper empty, to find the power needed for two temperature milestones: 200 C, as maximum preheat/charge temperature, and 270 C, as maximum hot air temperature during roast. This is the power range where you should play from now.
Then I would preheat and charge at 175-200 C, ramp slowly for 4 minutes to 240-250 C, and let there until FC. Depending on the timings recorded for dry end and FC, I would adjust power levels for next roasts.
If FC not happens until minute 12, I would try less beans next roast. Pushing temperature up above 270 C would led to roasting defects.
 
mtbizzle
That is good to know that there is another safety mechanism. I removed the metal sheet to 'disable' the thermostat.

Quote

I would try various power levels with the popper empty, to find the power needed for two temperature milestones: 200 C, as maximum preheat/charge temperature, and 270 C, as maximum hot air temperature during roast.
Then I would preheat and charge at 175-200 C, ramp slowly for 4 minutes to 240-250 C, and let there until FC. Depending on the timings recorded for dry end and FC, I would adjust power levels for next roasts.
If FC not happens until minute 12, I would try less beans next roast. Pushing temperature up above 270 C would led to roasting defects.


Excellent, thanks Renatoa. When you say measure empty for the 200C and 270C points, I am thinking to measure low in the sifter, near the mesh, and observe for what % power gives a steady temperature plateau at 200C/270C.

I have been thinking of doing this mod to the Poppery 2, without bypassing the thermal fuse: https://ineedcoff...-roasting/. In short, this mod places the main heating coil on one line, and the fan and minor heating coil on another line. Use fan speed controller for the main heating element only. Constant full speed for the fan, adjustable temperature, remove thermostat but keep thermal fuse.

Then use the 200C power level as my pre-heat setting, charge, gradually increase power to the 270C power level over the first few minutes. I do have one thermocouple + multimeter, which will allow me to measure temps while it is empty, but the sifter is not wired with thermocouples to give roast temps right now. I'm not sure if just dropping the thermocouple wire into the beans that are being stirred will be very useful, but I could try to run it through a small hole.
Edited by mtbizzle on 05/20/2020 5:42 PM
Roast: Kaldi wide, SR800 + projects
Grind: Lab sweet, Bentwood, giota w/ MP burrs, Commandante
Pull: Decent, La Pavoni, Elektra Microcasa a Leva, Faemina anno 60, Kim Express
 
mtbizzle

Quote

Gullygossner wrote:
This weekend I attempted to use a poppery 1 heat/fan unit as the heat source on my KKTO...
I suspect air poppers can?t achieve the same outlet temperatures as heat guns since the retention time over the heating coils is less and I suspect the airflow is higher.


Gully, if there are any mechanisms to enforce a temperature ceiling in the poppery 1, like the thermostat or thermal fuse, did you do anything to these?
Roast: Kaldi wide, SR800 + projects
Grind: Lab sweet, Bentwood, giota w/ MP burrs, Commandante
Pull: Decent, La Pavoni, Elektra Microcasa a Leva, Faemina anno 60, Kim Express
 
Gullygossner

Quote

mtbizzle wrote:

Quote

Gullygossner wrote:
This weekend I attempted to use a poppery 1 heat/fan unit as the heat source on my KKTO...
I suspect air poppers can?t achieve the same outlet temperatures as heat guns since the retention time over the heating coils is less and I suspect the airflow is higher.


Gully, if there are any mechanisms to enforce a temperature ceiling in the poppery 1, like the thermostat or thermal fuse, did you do anything to these?


Yes the thermostat has been removed and the fan/heater are on different circuits with the heater being controlled via an esp8266/ssr combination.
 
mtbizzle

Quote

As initial tuning, I would try various power levels with the popper empty,


Just did some temperature tests of the empty flour sifter atop Poppery II, after removing thermal switch. Probe at bottom of flour sifter. Power adjusted w/ fan speed controller. Max temperature I was really getting, before plateau, was 190C.

Horribly ugly line chart, but I don't want to fiddle with making it prettier Grin

i.imgur.com/PYz2J1Z.jpg

Notes:
-'light': light was plugged into same outlet as popper and powered on.
-'direct wire': popper wired directly to outlet, no fan speed controller.

Temp plateaus (around 2 minutes):
60% power: 130C
75% power: 150C
90% power: 180C
100% power (wired thru fan speed controller): 185C
Direct wire: 190C

Certainly not getting the 270C Renatoa mentioned, at least in the hot air flowing freely, through empty popper/sifter.

Are there any easy ways to 'insulate' a flour sifter... :thinking:
Edited by mtbizzle on 05/21/2020 10:18 PM
Roast: Kaldi wide, SR800 + projects
Grind: Lab sweet, Bentwood, giota w/ MP burrs, Commandante
Pull: Decent, La Pavoni, Elektra Microcasa a Leva, Faemina anno 60, Kim Express
 
renatoa
What about reducing the airflow ? No need for beans levitation in a sifter.

Yes, 190 C could be used for cold brew roasts only, not for medium/city.
This test shows how big is the temperature gradient between the the bottom of the can versus the surface of beans pile, thus the importance of having a vertical movement for an even roast.
 
mtbizzle

Quote

renatoa wrote:

What about reducing the airflow ?


Reducing airflow independent of the heating elements would require some parts I don't have. Possible in the future, but not in the short term.

Quote

the importance of having a vertical movement for an even roast.


Good point -- I do try to 'scoop' the beans in my poppers up a bit, when I stir them...

Did a test run with 100g of natural yirga (roasts very unevenly in my past experience):
i.imgur.com/DZujGWA.jpg

My goal was to see if, and when, first crack would occur. Unfortunately I couldn't hear any cracks. Gradually ramped up power over 6 minutes. Ended roast just before 17 minutes. 12.2% weight loss. This bean seems to always look uneven and half orange, but regardless, 12.2% loss at 17 minutes -- does not seem to be hot enough to be roasting.
Edited by mtbizzle on 05/22/2020 9:01 PM
Roast: Kaldi wide, SR800 + projects
Grind: Lab sweet, Bentwood, giota w/ MP burrs, Commandante
Pull: Decent, La Pavoni, Elektra Microcasa a Leva, Faemina anno 60, Kim Express
 
mtbizzle
Just finished first test roast on my functional, but not really finished, heat gun + flower sifter. The heat gun is a wagner 700 (or 750?) which has a lot of heat and fan settings. I was somewhere around 730-850 setting the entire roast, max fan speed.

Given what you see... the stand was moving around a lot during the roast, so I had to adjust a lot. I should really get a wired drill + stand for this...

i.imgur.com/LjmUkvu.jpg

Rwanda Rulindo Bushoki Peaberry from SM
135g charge
Approx. 17% loss
Approx. 14:30 drop

Tom recommends City - Full City. Unfortunately didn't hear first cracks, but eventually my flour sifter turned into a smoke stack and I heard cracks, so pretty sure this is a light Vienna roast.... (picture under LED light)

i.imgur.com/MSXQTUF.jpg
Roast: Kaldi wide, SR800 + projects
Grind: Lab sweet, Bentwood, giota w/ MP burrs, Commandante
Pull: Decent, La Pavoni, Elektra Microcasa a Leva, Faemina anno 60, Kim Express
 
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