Koffee Kosmo Roaster with Heat Gun as Alternative Heat Source

Koffee_Kosmo

This thread topic has been posted to record alternative sources of heat for the Koffee Kosmo roaster design

For some time now I have had correspondence with details of DIY modifications by owners and requests to build a special KKTO roaster for the not so DIY type 

So I thought that a pictorial is in order for Crema members to see some handy work

The following KKTO roaster was built with pots supplied by the current owner
I had to redesign the agitator blade to overcome a very flexible base on the perforated pot

A traditional set up using a stand for the Heat gun
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Koffee_Kosmo

The second KKTO roaster on the list is owned by Crema member - bcspark Had a trial session with Barry kindly bringing his roaster for appraisal He originally did some modifications to the TO but eventually the element failed Barry on another modification removed the electric section of the Turbo Oven and sealed it with a metal plate On this plate he made a hole for the Heat gun access The heat gun he uses is a commercial type with digital heat adjustment to 650 deg Celsius called Stienel (see photos) The day of the trial we did 1 kilo of a Colombian Bachue and it went without a hitch Photos Heat Gun - Stienel HG 2310 LCD Electronic Attachment not found.Attachment not found.Attachment not found.Attachment not found.Attachment not found.Attachment not found.

UNM

how do you get the beans out to cool? Or do they cool in the roaster? Looks like a separate cooling tray, but all that hardware over the pot would make it tricky to tip the beans out quickly wouldn't it?

Koffee_Kosmo

on 1354441408:

how do you get the beans out to cool? Or do they cool in the roaster? Looks like a separate cooling tray, but all that hardware over the pot would make it tricky to tip the beans out quickly wouldn't it?

See post 2 The KKTO roasters utilize a separate bean cooler The upper pot insert is raised and the beans poured into the cooler KK

Rider

If you are going to use a heatgun it would seem to me the KKTO is overkill. I would envisage the benefits of a KKTO is being a sealed unit... i.e. an oven or chamber. Using a heatgun you be be way more financially ahead by buying an el cheapo bread machine from K Mart for 30 clams... Thoughts?

Koffee_Kosmo

on 1354451290:

If you are going to use a heatgun it would seem to me the KKTO is overkill. I would envisage the benefits of a KKTO is being a sealed unit... i.e. an oven or chamber. Using a heatgun you be be way more financially ahead by buying an el cheapo bread machine from K Mart for 30 clams... Thoughts?

The second unit ( see post 2 ) I posted actualy uses the original concept of a sealed unit but the heat source has been replaced KK

Rider

on 1354452318:

The second unit ( see post 2 ) I posted actualy uses the original concept of a sealed unit but the heat source has been replaced KK

Indeed. My apologies. That makes more sense rather than open air heat gun. Rider

UNM

The second post  appeared while I was composing my previous post, or perhaps I just missed it. That is a better setup as I can see it would be possible to get the beans out fairly quickly. Also no chaff blowing around

Koffee_Kosmo

on 1354497868:

The second post  appeared while I was composing my previous post, or perhaps I just missed it. That is a better setup as I can see it would be possible to get the beans out fairly quickly. Also no chaff blowing around

Correct And this feature - choosing a heat source -  will be part of the new roaster design I have to email some people to see if I can get the electronics part altered to be programmed to cater to set and user imputed profiles via the readings of a thermocouple in the bean mass KK

bcspark

on 1354518551:

and for those more concerned with external appearances Thanks Paul for posting my setup.Still roasting 500-1000grms with the same results.  Bcspark I think for $1250 we did ok. one month on no issues yet.

bcspark

I have finally made a new top for my KKTO. As shown in previous post I have chosen a heat gun as heat source. The Steinel gun is programmible in both heat and air supply giving heat from 50deg to 650deg in small increments. Air supply is variable and separate from heat control. The new head module is made from 3mm marine grade SS ,hard as, and complete unit is SS. Below are some photos of the finished article . With all variables plus CS monitoring equipment I can roast to any profile 500grm to 1kg of green beans. The Steinel is an industrial unit designed to work continually at full program. Attachment not found.

Brett H

Lovely work mate! 

Koffee_Kosmo

on 1365297649:

I have finally made a new top for my KKTO. As shown in previous post I have chosen a heat gun as heat source. The Steinel gun is programmible in both heat and air supply giving heat from 50deg to 650deg in small increments. Air supply is variable and separate from heat control. The new head module is made from 3mm marine grade SS ,hard as, and complete unit is SS. Below are some photos of the finished article . With all variables plus CS monitoring equipment I can roast to any profile 500grm to 1kg of green beans. The Steinel is an industrial unit designed to work continually at full program.

Very nice with an industrial feel Barry  :thumb: just the way I like it We may have spoken about this adaptation when I had the pleasure to road test your KKTO roaster at Barazi One of those design aspects we talked about may be part part of the new KKTO design ? We need to get together again for another roast session KK

bcspark

As suggested KK and I. Met at Chrises,Bezzera home.This was to roast Chris some of his beans for his use .name of bean escapes me as I was unwell . Paul and I roasted 1 kg in my KKTO with the Steinel HG source .My learning curve was refined by roasting with Paul. Perhaps  Paul can fill in the details as he was active with the camera. Paul thank you again for for passing on your experience it was well noted. bcspark

Koffee_Kosmo

I was with Barry to test the new modified roaster using a heatgun as the heat source Works a treat Thanks Barry for allowing me to test and observe it was a success Attachment not found.Attachment not found.

bcspark

Thanks KK sick and all that I was I would not have missed our session for anything. Learnt so much  bcspark

bcspark

Still fiddling . Decided to take my heat source closer to bean mass as you have stated ,ideally 50 mm above mass. Have added a 50mm SS tube to under side ,approx. 80mm long .Still experimenting as I have only done 2 roasts but both showed better results. I will post some photos when tests are complete        bcspark

bcspark

Still not satisfied . Heat source is to one side so difficult to get hot air to 50mm of beans. looking at new top to centre HG. Having said this I have used a new profile to roast with an extended drying time ie from TP to 100deg at least 3-4 mins . Seems to be working as my Buf Remera roast became a smoke screen during rolling 1stC at 216deg  :thumb:

Koffee_Kosmo

You can fit a DIY diffuser nozzle under the plate to scatter the heat direction A lot easier than a new plate KK

bcspark

In the process of design of same .Will have to go to mates workshop to cut and weld 50mm SS hollow round. Just considering which will be better outcome for air supply

bcspark

on 1376874401:

You can fit a DIY diffuser nozzle under the plate to scatter the heat direction A lot easier than a new plate KK

Job done now heat is more centred and closer to beans.All I have to do now is roast ,rest and drink

bcspark

KK Have roasted two 600grm batches with the heat source 20mm above agitator post.The opening of the angled 40mm pipe begins at the post and back to the side of pot .This opening is cut horizontal to pot bottom giving a substantial opening.Both roasts have produced dark roasts around the centre which do not mix with the outer beans producing a mixed roast. Tested with 650grm of greens agitating ,dropped some dark beans into centre ,found the dark beans never left the top and centre .  bcspark

Koffee_Kosmo

That's unusual ? However roasted beans will react differently when added to green beans - try painting some green beans red and test again I am wondering -  If it did not do that before why is it doing it now? Just as a quick experiment - attach a dog type paper clip to the top of the agitator blade and observe what happens Beans may just need a kick along quicker due to extra heat concentration KK

bcspark

Never had this problem because the flow was directed to faster moving out side beans.Do you think I would be better to turn the nossle more to the outside. There has to be more agitation at the extremity compared to centre

Koffee_Kosmo

on 1377398844:

Never had this problem because the flow was directed to faster moving out side beans.Do you think I would be better to turn the nossle more to the outside. There has to be more agitation at the extremity compared to centre

Yes there is more agitation on the outside The inside is the intermittent rest period where the beans dive down and work ther way slowly to the outside So it makes sense to aim the heat to the outside KK

bcspark

on 1377400674:

Yes there is more agitation on the outside The inside is the intermittent rest period where the beans dive down and work ther way slowly to the outside So it makes sense to aim the heat to the outside KK

Just completed test roast with heat directed toward outside problem fixed. Unbelievable that a small  mod can upset the apple cart .Me thinks I will leave sleeping dogs lie and just enjoy roasting . Thanks KK

Koffee_Kosmo

on 1377403935:

Just completed test roast with heat directed toward outside problem fixed. Unbelievable that a small  mod can upset the apple cart .Me thinks I will leave sleeping dogs lie and just enjoy roasting . Thanks KK

Very good  :thumb: Keep me in the loop on some future roasts to monitor consistency KK

bcspark

Did a test roast with a 45deg crank in the pipe eexstention .Found this slow roast down ,not delivering enough heat to bean mass. Conclusion is that the pipe exstention is to be straight ,meaning no flow restrictions to heat & air flow .Another test roast needs to be done but every body I supply are full up

bcspark

on 1377641423:

Did a test roast with a 45deg crank in the pipe eexstention .Found this slow roast down ,not delivering enough heat to bean mass. Conclusion is that the pipe exstention is to be straight ,meaning no flow restrictions to heat & air flow .Another test roast needs to be done but every body I supply are full up

Used 100mm extention to HG, roast was ok but not enough control. Decided to go back to 50mm and found more control and available heat and fan . The resultant roasts were done to what I think is near perfection for a home roaster,CS8 226deg 16-17min. A

bcspark

on 1378960637:

Used 100mm extention to HG, roast was ok but not enough control. Decided to go back to 50mm and found more control and available heat and fan . The resultant roasts were done to what I think is near perfection for a home roaster,CS8 226deg 16-17min.

For some unknown reason my reply was posted before I finished. To finish I now let the bean temp rise after  preheat and load to ramp from bottom heat to 100deg to in  5min giving the bean time to dry and stabilize .From 100deg to target I apply 12-14deg/min

Koffee_Kosmo

I like the centralised heat distribution of the Turbo Oven If that pattern can be replicated I believe that you will be on a winner KK