Turbo Oven Roaster: any comments/criticisms please

[Bean_Bear]

I have just done my first serious roast in my newly built roaster and I’m wondering if anyone has any comments or criticisms of my design.

I tried to build it as cheaply and easily as possible. I used a K Mart convection oven with the spacer ring and a sheet of aluminium as a chamber. The base is an old aluminium pot, the motor is recycled from an old battery operated suction pump (could have used a windscreen wiper motor though). For insulation between the roasting chamber and the base I used a piece of cement sheet. The driveshaft is a cut down 6mm allen key. The stirrer is a 3/8” nut with 3 holes drilled into 3 flat faces and 3.1mm wire inserted and silver soldered into place, the wires butt up against the allen key to drive the stirrer. The second most expensive part was the high temperature silicon sealant (the reddish stuff everywhere). Anyway, go hard, I have thick skin .

I have included a plot of the first real roast completed in the roaster.

[A_M]

Re: Turbo Oven Roaster: any comments/criticisms please

A cut down KKTO and looks well done...

1: Depth to the beans suggests a good amount of direct heat...

2: Chaff removal ?

3: What is the max load of green beans..

4: Where is teh temp probe placed or are you plotting manually from the built in gauge ?

5: What is the noise like and teh ability the hear 1 and 2 crack ?

6: Am assuming no one else around to touch the outer skin ? (HOT = OHS)

[Koffee_Kosmo]

Re: Turbo Oven Roaster: any comments/criticisms please

Good job on the KKTO
Overall its well made and sticks close to the original design [smiley=thumbup.gif]

A few points

1] Chaff separation should work the same but the fine chaff may collect on the bottom of the pan without exit holes

2] I recommend external insulation both for heat retention and safety

3] Overall volume is best at 7 to 9.5 lt

4] I favour a perforated roast chamber for equal heat distribution from all angles

Keep us in the loop with results

KK

[Thundergod]

Re: Turbo Oven Roaster: any comments/criticisms please

Id be worried that the stirring action might not be adequate with such thin arms.

However, the proofs in the pudding, how did that first roast go?

I like what youve done.

[Bean_Bear]

Re: Turbo Oven Roaster: any comments/criticisms please

Thanks AM

1: Depth to the beans suggests a good amount of direct heat...

I think that’s true, is that a good thing?

2: Chaff removal ?

Most of the chaff was in the bottom of the roaster, just like in a KKTO.

3:  What is the max load of green beans..

I did 300g last night, and 350g previously, at the moment that’s about all I want per week. I think it should do about 400g to 450g without a bigger tray, time will tell.

4: Where is the temp probe placed or are you plotting manually from the built in gauge ?

I used two K type probes on a Fluke 52, one in the beans, one in the air. The one in the air reads about the same as the beans while heater was off, and about +40oC when heater on. I took readings once a minute and plotted with Excel. I am thinking of getting the CS DMM and using the Roast monitor (especialy if I can close the loop 8-))

5: What is the noise like and the ability the hear 1 and 2 crack ?

Stirrer is noisy without the beans in the pan, but quiet with beans. The oven is fairly quiet too. I have very little experience, but I heard 1st, and 2nd crack easily.

6: Am assuming no one else around to touch the outer skin ?  (HOT = OHS)  
 

It’s as hot as hell on the outside of the spacer, the manufacturer put a triangle with wavy lines on it pressed into one side of the ring so all is good. I am going to have to insulate or shield the thing for when the kids are around.

Thanks KK, you are the messiah .

Do I have your permission to call my roaster a “KKTO-lite”, I was aiming for hybrid KKTO/SCTO.


1] Chaff separation should work the same but the fine chaff may collect on the bottom of the pan without exit holes

Chaff exits fairly well, I will drill the bottom of the pan, but more to increase friction, the stirrer tends to push the whole bean mass a bit.

2] I recommend external insulation both for heat retention and safety

I will do that, I am looking for fibreglass mat (I think :-?).

3] Overall volume is best at 7 to 9.5 lt

Volume of my roaster is about 6 lt, but is low profile and more subject to direct heating I will have to change the volume on the next version.

4] I favour a perforated roast chamber for equal heat distribution from all angles

I have perforations at hand, I was thinking of installing several hundred of the 3mm or 4mm variety. Once installed they are very hard to uninstall ;D ;D .

Thanks for the feedback so far BB.
 

[Bean_Bear]

Re: Turbo Oven Roaster: any comments/criticisms please

Id be worried that the stirring action might not be adequate with such thin arms.

However, the proofs in the pudding, how did that first roast go?

I like what youve done.

Thanks Thundergod (is that TG?). I am really happy with the stirring so far, it is speed dependant and must go CCW. I have tried running from 2 volts out to about 7 volts (20 rpm to 75 rpm) it works best about 35 to 40 rpm. At 12 volts it spits all the beans out of the pan ;D ;D ;D ;D :-? ;D ;D ;D.

[Andy]

Re: Turbo Oven Roaster: any comments/criticisms please

Great looking result, very nice work too!

How do they taste (which is the reason we roast)

[Bean_Bear]

Re: Turbo Oven Roaster: any comments/criticisms please

Thanks Andy,

Roasted them last night, I will try them tonight, and tomorrow night and the next night.........

My last batch were a bit underdone, but I drank them all, they were starting to taste good when I ran out. I think these will be much better.

I will post my opinion of my roast tomorrow (completely unbiased ;D).

[Koffee_Kosmo]

Re: Turbo Oven Roaster: any comments/criticisms please

Id be worried that the stirring action might not be adequate with such thin arms.

However, the proofs in the pudding, how did that first roast go?

I like what youve done.  

Thanks Thundergod (is that TG?). I am really happy with the stirring so far, it is speed dependant and must go CCW. I have tried running from 2 volts out to about 7 volts (20 rpm to 75 rpm) it works best about 35 to 40 rpm. At 12 volts it spits all the beans out of the pan ;D ;D ;D ;D :-?       ;D ;D ;D.

I spent countless hours fine tuning the agitator to have a complete mixing action rather than to push a mass of coffee beans around a bowl action

KK

[Thundergod]

Re: Turbo Oven Roaster: any comments/criticisms please

Thanks Thundergod (is that TG?).

Youre welcome. TG is fine.

[A_M]

Re: Turbo Oven Roaster: any comments/criticisms please

but I drank them all, they were starting to taste good when I ran out.

Happens to me all the time ;D

[Dimal]

Re: Turbo Oven Roaster: any comments/criticisms please

Gday BB.....

Im with Andy, thats an excellent result in the photo above mate. Just try a brew (or three ;D) each day until you discover when the roast tastes perfect, for your palate. Also, I wouldnt be in too big a rush to change your initial design very much; it already looks as though its doing a great job. Probably just limiting any changes to fine-tuning enhancements will produce the best results in the cup.

Great stuff mate.... [smiley=thumbsup.gif]

Mal.

[tedk]

Re: Turbo Oven Roaster: any comments/criticisms please

Looks great.
You guys have beaten me hands down.
Ive been contemplating a halogen lamp roaster for a while but the round2it takes a lot of getting....
One question... how do you go transferring to cooler?
Ted

[Bean_Bear]

Re: Turbo Oven Roaster: any comments/criticisms please

Ive been contemplating a halogen lamp roaster for a while but the round2it takes a lot of getting....

I was going to start with a popper, but I liked the concept of the Turbo Oven roasters, then I saw a Turbo Oven on special, game over.

Im not finished yet, but what I have done so far took less time than I thought it would. I have a plan in my head, and a small tape measure in my pocket, when I see something that looks like it belongs in my roaster i measure it and decide. So far Im into it for about 15 hours labour and about $65 parts. Pretty cheap hobby (so far) with a short payback time.

One question... how do you go transferring to cooler?

I use my welding gloves, I tried gardening gloves but you have to be quick.

How do they taste (which is the reason we roast)

The beans in the picture above taste good so far, probably a little bit too dark. They seem to be best about 3 days after roasting. I find myself thinking about extending the time from 1C to 2C, or what if I do this or that, It’s a bit like brewing beer, but with much quicker results.

BB

[Koffee_Kosmo]

Re: Turbo Oven Roaster: any comments/criticisms please

tedk wrote on 27. Aug 2010 at 22:20:
One question... how do you go transferring to cooler?



I use my welding gloves, I tried gardening gloves but you have to be quick.

The original KKTO roaster was a closed style and I used oven gloves

For the new kit design I went for the safer option of the 2 pot system

However the original design still works great

KK