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JackH
OfflineAdmin
· 07/04/2020 10:27 AM
Happy 4th of July! jazzyhands

JackH
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· 06/24/2020 7:58 AM
@Mark McCornack, Please post your question in the forum.

Mark McCornack
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· 06/15/2020 9:28 PM
Hi! Looking for a legacy inlet temp sensor on 13 yr old Gene Cafe. It seems they've changed it and now you need new mother board and new sensor. Any ideas where I can find compatibile old one? Mark

Samaniego
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· 06/09/2020 6:39 PM
Wich thermometers Can i buy for my roasting machine compatible with usb or macbook?

JackH
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· 06/05/2020 5:38 PM
peveleth, It is better if you start a post in the forum with your question. These shouts go away in time.

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Made another turbo roaster......
Mbb
My brother asked me to help him put together a turbo oven roaster.....so, i did.

The catch.....years ago i contemplated using a presto big kettle fryer as base for turbo roaster....provide additional heat. So chanced $35. Its thick aluminum, sized good, and holds heat. Its tstat works to keep it limited. Set on max 400, it held 410 when i tested. Or adjust it anywhere like . Wont scorch beans, but greatly speed roast heat input to get you to where the turbos high temps finish it slower.

I thought....might have to plug kettle into another circuit.
Nope. Both ran fine together on single 15a circuit, even w 2 light bulbs too, and the small motor, and my freezer. (Probably didnt cyce) Hmmmm....do the turbo really put out 1300w then? Id have to say....maybe no.

Used an 80 rpm motor i had laying around.

Result.....with maximum air temp reached in roaster under 450F...turbo was set on only 400....16oz reached 1st crack in 10 min....which was my goal. It was a good roast . Its a much rounder, fuller BT profile judging by the dozen data points i plotted, when compared to plots i made roasting 8 oz on scto in past. Heat can soak in by conduction when first charging after preheating, and the air temp doesnt drop far after removing lid to charge....i think it dropped from 400 to 375

Ive drank 50 lbs of the coffee i roasted to test it....the roast was good as any. I did experiment long ago removing turbo shield to put more heat in....that was bad, imo.



The walls hold heat. No insulation needed.

The agitator keeps bean moving out at wall, not center
Tilted a few degrees, thicker bean mass at bottom to embed tcouple in.


Seriously, this works well


Havent made adjustable sliding door to exhaust smoke/chaff yet. An opening is needed to hear 1C...too quiet to hear it without one, at least over the bean noise.
Edited by Mbb on 02/25/2020 2:08 PM
 
renatoa
welcome to forum

This post is cracking in the wind without pictures Grin
 
Mbb

Quote

renatoa wrote:

welcome to forum

This post is cracking in the wind without pictures Grin


Thats whats wrong with people today.....no imagination

Got a pic of what its seasoning 1st roast looked like.....this was to coat metal with oil, burn off residues, get feel for temps, etc. It went to garbage. Did a second one too.....black.

Ill try to post pic later

Btw...if you need wire source for bean agitator...
Try the 3/32" steel TIG welding rods at harbor freight
....you get a sheetload for $8 with 20% off coupon , they are 3ft long, copper coated....bendable by hand and pliers, or around forms. Lifetime supply.


images2.imgbox.com/f7/53/0RloadEZ_o.jpg

images2.imgbox.com/95/bc/xfPwWCjo_o.jpg

images2.imgbox.com/2c/a7/LZzSH1uf_o.jpg
Edited by Mbb on 02/25/2020 6:10 PM
 
Mbb
Agitator shaft

Motor shaft drives deep socket, running in wood block bearing.

Agitator bolt drops in. Spring wind keeps it snug in socket. Yep, you can drill a hole in ss bolt . Patience is key to not burn bit.


images2.imgbox.com/1d/74/jggHHhDq_o.jpg

Takes 10 minutes to bend an agitator....permanent thermocouple will pass between upper and lower parts.

Almost anything works to agitate at 80 rpm.....

images2.imgbox.com/15/47/pnunA01V_o.jpg
Edited by Mbb on 02/25/2020 8:50 PM
 
Koffee Kosmo
I have used this design about 9 years ago
However in that build for a friend I used an electric frypan not a pot

Should work well but I chose the current roaster design because of chaff and ease of use issues

KK
I home roast and I like it
Blog - http://koffeekosmo.blogspot.com/
Bezzera Strega: Mazzer Robur Grinder: 5 Box hand grinders: Pullman Tamper Convex: (KKTO) Turbo Oven Home Roaster: CONA Glass Rod Syphon: Pyrex Brewer:
 
http://koffeekosmo.com.au
Mbb

Quote

Koffee Kosmo wrote:

I have used this design about 9 years ago
However in that build for a friend I used an electric frypan not a pot

Should work well but I chose the current roaster design because of chaff and ease of use issues

KK


I've never had a chaff issue. The turbo roasters I've made always ejected the chaff.....well at least you might have to be that you got to blow it away when you're done..or vacuum it... But there's none left in the roaster.

what I was looking for is a homegrown design to get you the first crack with one pound in under 10 minutes and this can do it

What I really like about it, is it sturdy, heat to spare, and significant heat from conduction too.
(
I really expected it would need to be plugged into two breaker circuits....or plug into dryer socket and use only one leg for 120. Thats main reason i never did it years ago, figured it would be hassle. Still amazed it can run on one circuit..(my compressor thats borderline for circuit trips this garage circuit [img][/img]every time it stops..so i know it works. )

Had in my head to cut the kettle shorter.......still might , but it works as is. Time will tell.
Edited by Mbb on 02/26/2020 7:34 AM
 
Mbb
Short agitation clip
I like it tilted a little.
Gives a thick bean mass on one side to put probe in, turns over better, its tumbing across bottom, not just flowing in circle around outside. Keep beans on hot surface moving .


Edited by Mbb on 02/25/2020 9:10 PM
 
Mbb
Artisan curve
Still struggling with the flick at end of 1c

Working well
16 oz
Turbo running 50-70% mostly
Base running only 0-20 %
Expect it could do 1.5 lbs if tried


images2.imgbox.com/30/90/G3DoqsN3_o.jpg
Edited by Mbb on 04/26/2020 7:29 PM
 
renatoa
Me too turning it tilted for 250 grams, for complete probe immersion, and also looks agitation is better, in the colored bean test.
I turn the machine flat/horizontal from loads of 333 grams and up.

What we see at the end of FC (yellow area) is not a real flick, no idea what could be, but physically you can't have such fast variation in temperature at that point, even turning power full on-off. I suspect a probe glitch rather. A look of real temperatures log could help to diagnose this.
Can you configure Artisan to show power levels too ? I am interested to see your heater strategy.
Anyway, nice results !
 
renatoa

Quote

Mbb wrote:

What I really like about it, is it sturdy, heat to spare, and significant heat from conduction too.


Didn't noticed this phrase at the time of posting.

Nope, you don't need nor want conduction heat in your beans at all, this means scorching.
You can't transfer even 1% of the heat through the contact of a spherical surface, if you insist you will have burned beans, like the barbeque/grilled meat, in the contact points with the iron.
A well designed and speed tuned drum does not transfer any iota of heat by surface contact, the goal of vanes design and optimal RPM is to keep beans as much as possible in a continuous "rain", at the limit of centrifugal "zero gravity" suspension state, in order to favor convection heat transfer, from air surrounding beans.
This design goal does not apply to TO roasters, and we shouldn't worry about burnt beans, because the roasting pan/insert is not heated by a flame, but is immersed in the same hot air as the beans, so they heat together.
Would be a lot more beneficial to have a perforated pot, to favor air circulation, instead a solid pot, as I see in the clip.
 
Mbb

Quote

renatoa wrote:



What we see at the end of FC (yellow area) is not a real flick, no idea what could be, but physically you can't have such fast variation in temperature at that point, even turning power full on-off. I suspect a probe glitch rather. A look of real temperatures log could help to diagnose this.
Can you configure Artisan to show power levels too ? I am interested to see your heater strategy.
Anyway, nice results !



Its the standard flick that always occurs near end of 1 C that Rao has written do much about avoiding , its real, not an artifact. It can cause roasty "baked" flavor if excessive.
Edited by Mbb on 04/27/2020 4:38 AM
 
renatoa
What we call standard Rao flick occurs at the START of FC, due to the crack process itself, the exhaust of steam from cracked beans.

Quote

The flick is initiated when chemical reactions within the beans switch to an exothermic state and begin producing heat, rather than absorbing heat.


https://blog.oilslickcoffee.com/2016/...ick-crash/

A further flick is an anomaly, could appear in drum machines only, if the power/air balance is not well managed, being one of the most undesired "feature" of these machines.
I don't see any thermodynamic reason to have such flick in a TO machine, if you don't have a major change in power level.
The best approach for using a TO is as much as possible constant power across the whole roast, very small changes at the end, before FC, and rely on natural machine curve.
 
Mbb

Quote

renatoa wrote:

Quote

Mbb wrote:

What I really like about it, is it sturdy, heat to spare, and significant heat from conduction too.


Didn't noticed this phrase at the time of posting.

Nope, you don't need nor want conduction heat in your beans at all, this means scorching.
You can't transfer even 1% of the heat through the contact of a spherical surface, if you insist you will have burned beans, like the barbeque/grilled meat, in the contact points with the iron.
A well designed and speed tuned drum does not transfer any iota of heat by surface contact, the goal of vanes design and optimal RPM is to keep beans as much as possible in a continuous "rain", at the limit of centrifugal "zero gravity" suspension state, in order to favor convection heat transfer, from air surrounding beans.
This design goal does not apply to TO roasters, and we shouldn't worry about burnt beans, because the roasting pan/insert is not heated by a flame, but is immersed in the same hot air as the beans, so they heat together.
Would be a lot more beneficial to have a perforated pot, to favor air circulation, instead a solid pot, as I see in the clip.



See the temperature rise from the being charged to the turning point + in 50 seconds..... The BT go from room temperature to 240 degree by absorbing the heat stored in the preheated base......the turbo oven is off...... The base heating is ....also off........during the initial ~1 min heat soak after charge. The same as charging a drum roaster. You wont scorch if you keep the metal temperature low enough and beans moving. However, this preheat temperature has a lot to do with initial heat infuson into beans and how fast you reach 1 C .


When we say conduction.....the hot metal also heats the air in contact with bean mass ..... It puts in a lot of initial heat while keeping turbo air temp low also. Enough to reach first crack in 5 minutes with 1 lb. I know this same turbo oven wouldn't do that in 15 minutes in another scto i have. A much smaller, insulated bottom scto. Not without reaching high enough air temps ~500 F to make coffee bitter. Certainly not on 80% power. Well maybe if you took the shield off but I can tell you that made bad coffee. Bad idea.

You will notice on the artisan my air temp only reached 450, I start the power at 90% until the Delta BT reaches 30 f then back it off to about 70% and then back it down more going into first crack.
Edited by Mbb on 04/27/2020 6:01 AM
 
Mbb

Quote

renatoa wrote:

What we call standard Rao flick occurs at the START of FC, due to the crack process itself, the exhaust of steam from cracked beans.

Quote

The flick is initiated when chemical reactions within the beans switch to an exothermic state and begin producing heat, rather than absorbing heat.


https://blog.oilslickcoffee.com/2016/...ick-crash/

A further flick is an anomaly, could appear in drum machines only, if the power/air balance is not well managed, being one of the most undesired "feature" of these machines.
I don't see any thermodynamic reason to have such flick in a TO machine, if you don't have a major change in power level.
The best approach for using a TO is as much as possible constant power across the whole roast, very small changes at the end, before FC, and rely on natural machine curve.



From Rao:

"In a typical 10—14 minute drum roast, the flick occurs approximately 90-120 seconds after the onset of first crack."

This is the last 0- 30 seconds of 1C.

Consistent with my experience as well.

by managing the environment you can prevent this BT from shooting up at that point in time

During 1C releasing water cools the beans. When this stops, temperature suddenly begins rising faster

Cutting heat into the exotherm at start of 1C to manage that can accentuate it. Which is why Rao says don't touch your heat 45 seconds before 1 C.

https://www.cropster.com/news/article...the-flick/

images2.imgbox.com/11/0e/WAIjYF47_o.png
Edited by Mbb on 04/27/2020 5:55 AM
 
renatoa
This could happen maybe because you are trying to mimic a drum roast with a TO as power source, a hybrid TO-drum approach, which is a novelty for most of us.
And brings all the issues and weaknesses of drum machines into play, that the original design using a perforated roast pan have eliminated, a true TO roast being mostly convective, with some IR addition if the bulb plate is modified. In our perforated pans the air circulation is permanent and what is driving the BT is mostly the air, so that beans cooling does not happen so pregnant as in a solid drum/pot.
I would stay away from your operating way, that hocus-pocus with heat-air in drum machines is a thing that exasperates me, I am much more comfortable with constant heat input.
Real drum machines indeed store heat into a drum, but in a 10 kg heavy cast iron bell, not a thin tin pot, as we have in our TOs.
As a result, they deliver heat at charge for significantly longer time, slowly, having turning point over 100 C and 2 minutes, instead under one minute and 100 C, as in a typical TO setup.

Pushing so much heat into beans, as FC in 5 minutes, is not a thing to brag, imo.

I am able to roast 500 grams with FC before minute 12 in my TO machine, I would check the power of the bulb, there are many counterfeits labelled as 1300, but 900W of real power.

Anyway, lucky me I am a light roast lover, never finishing FC, usually for me drop is in the 90 seconds after FC, so I am not worried to handle another issue of an already too complicated process Grin
Edited by renatoa on 04/27/2020 6:26 AM
 
Mbb
My only point
Manage a BT curve thru delta BT
Temp fluctuations in the delta BT cause issues, most notably roasty flavor.

I agree 5 min way too fast.

I would also say that a significant part of turbos heat is by IR, not just air. Blocking it slows it. In same way removing shield makes charcoal easily
 
Mbb
Few additions
Adjustable vent opening
And a fan that forces air thru
The fan is a 12-volt low pressure fan that is used to control my smoker I just put it on here instead and run it on manual so far... but I can use the PID and capabilities of it to control the ET or BT as well
... And it can program a multistep temperature profile.....

The airflow reduces smoke redults in cleaner taste
It also helps control temps better... It really helps with the flick at the end of first crack.

Added heat too early at 1C on this roast...it started popping a few at 375 and i jacked heat too soon.

images2.imgbox.com/bb/83/VTG9FeFS_o.jpg

images2.imgbox.com/54/6a/5mSzkeu0_o.jpg


images2.imgbox.com/98/89/eDHPpRs2_o.jpg

images2.imgbox.com/02/fb/Z6eGByJh_o.jpg
Edited by Mbb on 05/12/2020 8:23 PM
 
Mbb
Finding the forced airflow..... improved taste by eliminating smoke inside.

Also helps control flick...better than heat control
Cooling....is better than not heating

Not there yet, but getting better at it.
Goes kind of slow when you got to drink a pound of coffee every time you roast

autocharge didn't pick up on this roast for some reason and I forgot to click it until didn't see ror curve

I'm not using the adjustable vent opening so I'll probably just make a discharge tube there that directs the chaff into a catch container

images2.imgbox.com/a1/b8/lkep6Ad9_o.jpg
Edited by Mbb on 05/26/2020 9:02 PM
 
Gullygossner

Quote

Mbb wrote:

Finding the forced airflow..... improved taste by eliminating smoke inside.

Also helps control flick...better than heat control


This is a really interesting innovation! I find the smokey notes and lack of routing for the smoke to be the most off putting part of the kkto setup. Definitely got my wheels spinning on a similar way to modify my setup.

I have been experimenting with a longer burp period after first crack and that has definitely improved the flavour but it's a little tricker to repeat in an outdoor setting with varying temperatures.
 
mtbizzle

Quote

Mbb wrote:

Its tstat works to keep it limited. Set on max 400, it held 410 when i tested....

Hmmmm....do the turbo really put out 1300w then? Id have to say....maybe no.
...

Seriously, this works well


Sorry to jump back... three months, and elbow in w/ my own question. Mbb what you said in your original post caught my eye, not sure I am understanding you right, but maybe it'll help me a bit...

I found a nice deal on a used Flavorwave AX-797DH. It's a 1300w TO, has heat settings up to 500F and three fan settings.

I had read from some veteran turbo oven folks, most TOs are 1200-1400w, just get highest wattage you can. And have found one or two people using this one. Was a good price so I picked it up.

Did a quick test, with a thermocouple in the original glass oven, no beans or anything inside. Set to 500f and just measured temps.

Well, to my dismay... it began cycling off/on starting at 360f on my tcouple. Never really got hotter than 390-394f on my tcouple... so much for 500f..????

But Mbb... you seemed to say something about 400-410f on yours?

Hoping somehow what I saw w/ my test is normal, but it seems to me this TO won't roast coffee. Shock
Roast: Nostalgia popper
Grind: Comandante c40, Encore
Brew: v60, flair espresso, moka pot, french press, cezve w/ 'Scott Rao' water
Ask me about Tea!
 
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