Homeroasters - Home Roasting Coffee Community » BUILDING A ROASTER » Turbo Oven Roasters
Who is here? 1 guest(s)
 Print Thread
KKTO-inspired build with Nuwave Convection Oven
Cymen
Top  #1 Print Post
Posted on 07/18/2023 2:16 PM
I'm using a Freshroast SR800 with a OEM (as opposed to Razzo) extension tube. I'm really happy with it for the most part but as I mentioned in my introduction thread, I want to build a roaster I might be able to use a on sailboat. The FR might work but it was recommended to try a turbo oven-based roaster and I'm excited to do so because trying another roasting method is exciting, I get to build/tinker and the batch size should be 2x or more of what I can do with the FR + OEM extension tube.

I found a Nuwave convection oven at the thrift store for $9. It has digital controls and says it is 1500 watts. It's been used a little bit (grease on the interior) but the cling film is still on the display/button area so I guess not that much use. I've attached a photo of one that looks really close to what I found.

Next I need to find a pot and think about visibility. I'd like to be able to see the beans while they are roasting if possible. I'm debating between reusing the yellow-ish plastic sides and adding a pot inside with a stirrer or ???. Still thinking that through and I have some other DIY/jobs that need to be done first that are unrelated so don't have to figure it out right away.
Cymen attached the following image:
71qqanbytl_ac_sx679_.jpg
Edited by Cymen on 07/18/2023 2:25 PM
 
Cymen
Top  #2 Print Post
Posted on 07/18/2023 2:25 PM
So the bottom of the plastic yellow part is just a big ring. So I could probably find a tin about that size (or make something) and put a pie tin inside with a hole up through the bottom for a bean stirrer. Maybe make it adjustable in height for the pie tin that would hold the beans so I can move it up/down from the heat? The nice part about this approach is I can still reuse it for convection oven duties although I might rip into the unit and hook up a microcontroller so I can have more control (but I could program that for cooking too of course).

I put "KKTO" in the title but that might not be quite right :). I realized I could edit the thread title so I added "inspired" so I have more leeway to go off on some other path.
 
Cymen
Top  #3 Print Post
Posted on 07/18/2023 2:29 PM
Looks like Nuwave sells some sort of riser ring so you can expand the capacity. If I can find an affordable version of that, I could use that and some sheet metal or something similar to make the base? Then off to the bean chamber. I have a nice insert for a steamer that would work great. I'm using it in my bean cooler right now though but I can always change that up -- the shape of it is really nice for roasting beans and I even got this odd 3 way metal divider that came with it (it came from an earlier thrift store trip) that would work as a paddle with some work. I'll post a photo soon as it's easier to understand visually.
 
Cymen
Top  #4 Print Post
Posted on 07/18/2023 2:35 PM
I'm going to keep checking the thrift stores in case I find another one with a ring or something else that would make it more suitable. One thrift store sells them for about $9 and the other one that has had them closer to $30-50 (which is way too much). So I'll wait a bit and see what comes along unless I get impatient.

I think sheet metal and rivets would be one way to make a base. I've got a rivet gun already. Maybe some kind of pizza tin or similar for the base. The extender ring is on eBay but not sure it's worth going that route as I'd still need to DIY some more bits for it so might as well DIY it all?
 
Cymen
Top  #5 Print Post
Posted on 07/18/2023 5:00 PM
Forgot to mention that of course I'm going to do a bunch of reading here to see what others have done and what works. Not trying to reinvent the wheel.
 
HarryDog
Top  #6 Print Post
Posted on 07/18/2023 7:07 PM
I have done some testing with the convection oven (Only 1300 watts) on a cheap roaster (CafeMasy) just to see how it would roast. Interesting. The extra heat from the cheap roaster allows some flexibility on roast times and I like that.

I was able to get a stainless steel pot for cheap, a mistake on pricing and a Chinese colander that almost fit, might have to bend up the lip a bit. Trying not to eat up too much of the volume of the pot.

I was thinking of using a heat gun to add some heat/air under the colander, looking for a cheap stainless steel burner to place under it to try and apply some more even air flow? Going kind of slow over the summer.

To keep me in coffee I have started roasting 1 pound batches in my little modified popcorn popper and I have been surprised at how even the roasts are. Could use more heat, going to insulate the roast chamber next.
 
renatoa
Top  #7 Print Post
Posted on 07/19/2023 1:42 AM
One pound in a popper ?!!! Shock
Are you doing all thing huge there over the pond ? Grin
After the 8 cup flour sifter, 4 times bigger than the EU models, this is a new hit...
 
HarryDog
Top  #8 Print Post
Posted on 07/19/2023 4:34 AM
Yep, the little Popper that could. When I did the 1 pound lift test just with the small bench blower it looked good enough to try a roast. It could use more heat but I think some good insulation might just be the help it needs.

It has a 3 inch chamber, moves the beans way better than I thought it would. I don't think I will change anything now but a 3.5 or 4 inch chamber with bigger heater would be nice to test out.
 
renatoa
Top  #9 Print Post
Posted on 07/19/2023 6:04 AM
I can't even figure how tall could be one pound column in 3" diameter chamber... Shock
 
HarryDog
Top  #10 Print Post
Posted on 07/19/2023 8:11 AM
Just from memory, about 7.5 inches when moving, roasted around 9.5 inches.
Note the base is slightly tapered and glass is 3 inch inside diameter.
I can take a video or pics next roast when testing the insulation and get exact numbers.
 
Koffee Kosmo
Top  #11 Print Post
Posted on 07/22/2023 7:05 AM
Hi and happy to see more innovation in coffee bean roasting

It’s vitally important to get the agitation right you want your agitator to mix the beans not to just push them around
By doing so it makes the roasting a lot easier

And finally have you considered the chaff
Some beans release so much chaff that can virtually clog the roaster and possibly create a fire hazard

So you have some homework to do

KK
I home roast and I like it. Designer of the KKTO
Roaster Build information
https://homeroast...ad_id=1142

https://docs.goog...lide=id.i0
Blog - http://koffeekosm...gspot.com/

Bezzera Strega, Mazzer Robur Grinder, Pullman Tamper Convex,
(KKTO) Turbo Oven Home Roaster.
 
Web
CK
Top  #12 Print Post
Posted on 07/22/2023 10:17 AM

Quote

Koffee Kosmo wrote:
It’s vitally important to get the agitation right you want your agitator to mix the beans not to just push them around


Very true. Evenly agitated beans are essential if we want consistent roast results. Roaster908 had many many agitator designs researched to get it right. R&D = homework and cost in time and resources.
Edited by Koffee Kosmo on 07/23/2023 7:04 AM
 
Jump to Forum: