KKTO Roaster Finaly Completed

Bevo

:laugh:
After a few months of off and on its finally completed. Ran a test batch and it seemed to go well. I couldnt hear the cracking unfortunately, getting old, so just stopped when it matched a bean I had. On cooling the roast came out a tad lighter which is probably a good thing.
Contemplating a usb thermocouple, see how we go.

Switches on front are to start internal cooling fan, start agitator, start 240v bean cooler. Bean cooler plugs in to a socket in the rear but thought Id put a switch on the front? Suprised how litte radiant heat was under the unit and transferred into the agitator motor. Very please thus far.
Agitator arms need work, some variation on bean colour due I suppose to ineffective mixing. I saw the mods to the turbo oven, will definately do the cut out but not sure if the thermosat mod will make a difference?
Only one roast down I dont really know whats going on  ???

Inspiration came from Kosmo, of course :-)

derrilex

Looks good mate, well done. It appears to have more in common with my hybrid than the traditional KKTO  :D is it a halogen TO ? You should remove the heat shield as well.

Brett H

LEGEND!!! Sensational mate.... Welcome to the club. Many happy roasts for you Bevo!

Koffee_Kosmo

Well done Bevo I helped with a little advice as you were assembling the parts, but all the manufacturing work was by your hands Please measure the total volume of the roast chamber and see if its around the 7 to 9 litres as the ideal for the design As for the wire agitator design It can differ in shape based on the speed of your motor But it's best to stick to a general loop and bend as required ( see photo ) You may have seen the drawing in another post Attachment not found.Attachment not found.

Bevo

:doh: Derrilex I indeed did use your very cool looking roaster as the design master. Big cheers to you as well  No its not halogen it has two heating coils like a kettle. I saw a mod to cut three large holes in the base, would removing it be risky with the chaff? Kosmo I shall measure the chamber. The agitator, well, as I used a modified 1/2" socket extension I have to have the wire go through the shaft about an inch above the colander base so some artistic bending was required to get is down to the base close to the shaft. Yes, needs some work. A few teething issues to keep me busy. Cheers all, now the learning begins 

Koffee_Kosmo

Test agitation with some coloured beans as I do Keep in mind and favour a good mixing agitation over pushing the bean mass around the roast chamber KK

mycuppa

Good to see that you have worked out already that a cold beer makes the perfect beverage to consume when roasting coffee.

Bevo

Hi all, Ok , manufactured a new mixer which seems better. 3/8 isnstead of 1/2 inch . allows the whisk arms lower and straighter in the bowl. I just cant hear the cracks ?  I stand over the turbo oven staring into it, head almost pressed to the glass but nothing really alerts me to the cracking. I hear the occasional bean being scraped and flung around the chamber? Last roast, yesterday, was 580g. thermocouple in base of chamber under bean mass, temp peaked about 140' c ? 22 min 50 roast time and then thought Id best tip it out to cooler. most beans are brown, some dark brown and some very light. I added four bean varietys at once. Next time I think I will roast each family seperately. But its the cracking thats got me stressed. Do I need to know when it happens or just look for the colour of the bean as the indicator when to stop? I set up my laptop to record the temp/profile, it restarted for some stupid windows update right at the end :-( not going so well. Help.. Oh I also cut out some holes in the heat sheild of the TO as seen on the site.

Koffee_Kosmo

Check overall volume as I noted above Also insulate the outside to keep heat loss at a minimum KK

derrilex

Mine must be the quietest one out there and i can hear the cracks easily. But I can hear the cracks in KK's roaster easy enough and it's a noisy bugger. Check that the blades are not scraping on the bowl too much as this creates heaps of " background" noise.

Bevo

I measured the bottom pan 30cm x 6 = 0.0042428571428571385  m3 TO ring 32cm x 8 = 0.0064365714285714234 m3 added then to litres = 10.67L    if its calculated right. I suppose I could cut down the TO ring ?  not sure I would ever get it square though.

Bevo

Blade scraping, yes I did set them up very close to edges and base. I shall adjust them, cheers. Anyone have a good second hand hearing aid? :'(

Koffee_Kosmo

on 1382742333:

I measured the bottom pan 30cm x 6 = 0.0042428571428571385  m3 TO ring 32cm x 8 = 0.0064365714285714234 m3 added then to litres = 10.67L    if its calculated right. I suppose I could cut down the TO ring ?  not sure I would ever get it square though.

Yes that is your heat to volume ratio issue Try for 7 to 9 litres - including the dome of the TO As to cracks you will become accustomed to it and after a few roasts you will hear them KK

Bevo

Thanks all. Ok back to the workshop. I have noticed that I may be able to slide the TO ring down the outside of my bottom pan and the blue heat tubing makes a very tight seal. This would mean removing the stainless angled plate but I dont think this will interfere as the collander has feet to keep it off the bottom of the pot for air flow. I would just need to cut down the collander by 3-4 cm. This would leave the top lip/gunnel removed allowing a possible escape path for the chaf from the bottom? or maybe the TO fan will keep a positive pressure and keep it down the bottom. Well this is the plan, anyone see any red flags before I begin, better now than after I start cuting 

Koffee_Kosmo

Once the chaff is in the outer chamber it will stay there You can also make smaller legs KK

Bevo

Good to know about the chaff. Kosmo if I had a mill, no problem. The legs lock the collander in and would be very hard to reduce, they are only 16mm high so It will be much easier to cut the collander. I could even braze the lip back on if I feel extra keen. Cheers for the help, I feel Im getting close to a consistent roaster....

derrilex

I'd just chop the TO ring in half. That will get rid of 3 lt and put you right on the money. I did mine, easy peasy

Bevo

Sounds good. While out today the cheapo kitchen shop was selling halogen TOs for $39.95. Needles to say I grabbed one. See how we go, seems to be 10 degrees hotter and hopefully will light up the beans. sean edit. no same temp my mistake. After swapping diffuser plates, old one modified, the halogen lamp looks like it will work a treat, as well as being deaf (not hearing crack) Im going blind (cannot see beans change colour well), it all helps as I get old and frail.

derrilex

Halogens are the only way to go.  :thumb:

derrilex

I got rid of the plate totally and bent the fan blades a touch too. Works a treat. The halogen light gives a false colour to the beans too so don't rely on it. Use smoke ( as impending cracks) and sound ( as the actual cracks). When 2nd crack starts ( if you go that far) lift the lid and look at the beans. The true colour will be revealed. Then you can just leave them spinning in the bowl until 2nd crack really gets going or you like the colour.

Bevo

Cheers Dereilex Good info. I was going to fibreglass the pan and TO ring for heat retention, its just standard CSM aound 600gsm. I dont think the oven temps are high enough to damage the glass, not as if its a furnace. Your thoughts? alternatives?

derrilex

I fully wrapped mine in earth wool and

Koffee_Kosmo

This is a photo of Derrilexs roaster Attachment not found.

Bevo

Hi all. Well all the mods are done. Halved the TO ring to give me about 7.7 liter total volume, using 3/8 shaft for aggitator, fiberglassed TO ring and stainless plate for issulation, finished with a woven cloth. Plus the new halogen TO. Ran a roast today 300g to see if better. Well, temp climbed quickly, preheated to 140c then by 5 mins there was smoke, then loud cracking, oh man it was awesom. Then I heard lots of rolling cracking and by 9 mins there was cracking and smoke everywhere. lol Dumped into the cooler, very dark indeed. Well into second crack I would guess. I was so impressed, I can definitely tame this machine down to deliver the goods. Thanks all for the advice, youve solved my drama. Now I cant get the stupid roast program to save my entry, always something :-)

Koffee_Kosmo

Welcome to the KKTO owner / roaster club  :thumb: The roaster will roast up to 1 kg and the sweet spot is around 650 grams Keep an eye out on good mixing agitation for best results KK

Bevo

Thanks Kosmo. I shall start to take notes now and try to be consistant. Will try the red bean again and see how it mixes. Cheers  Sean