Twin heat source KKTO roaster

[badhabitroasters]

Thanks Paul. I'll take some measurements and see how far away I am but I think I'm probably well over 30mm. I guess I thought that your standard volume of 7 to 9 liters didn't necessarily apply because of the booster heater but if you say it does I believe you. I guess I thought that the roaster volume had to do with the available heat for a given volume. For my own understanding, can you please explain the how and why of the ideal roaster volume of 7 -9 liters?

Rob

[Koffee_Kosmo]

Thanks Paul. I'll take some measurements and see how far away I am but I think I'm probably well over 30mm. I guess I thought that your standard volume of 7 to 9 liters didn't necessarily apply because of the booster heater but if you say it does I believe you. I guess I thought that the roaster volume had to do with the available heat for a given volume. For my own understanding, can you please explain the how and why of the ideal roaster volume of 7 -9 liters?

Rob

Hi again Rob
it is correct that the volume has been calculated based on the available heat of the Turbo Oven
The speed of heat delivery and retention of heat inside the roast chamber is another story

The second heat source will allow for larger batches to be roasted by equalising and boosting the available heats parameters
It evens out the fan-forced heat applied on the roasting beans so the heat doesn't fluctuate up and down giving you an easy climbing heat curve to FC & SC

So the current volume parameters still apply until one exceeds the available heat watts X 2 fold

KK

[badhabitroasters]

I need to roast a 2 lb roast to know for sure but I'm somewhere between 2 and 3 inches from the surface of the brown beans. I'm not looking forward to taking my roaster apart as the insulation was a tough job and I was very happy with the way it turned out but I sure don't want to compromise here. So off with its head!!!

Thanks!

Rob

[badhabitroasters]

Steve, I've posted pics of my project to date on the Homeroasters.org forum in the Turbo Oven section if you're interested.

[Mono]

Thanks for the update Rob, will go have a look.

Steve

[Mono]

Well, an update on my roaster. I have never been totally happy with the bottom element as when I would turn it to up greater than a third it would start to smoke [slightly] and stink so I always kept the setting below this "threshold". My thought is that the deep fryer element is encased in alloy and is made to operate heating a volume of oil which isn't what I have been using it for :-(. Either that or it is some of the materials I have used to fit the element not enjoying the heat. Anyway I have been tossing the idea around for ages as I happen to have a spare arcosteel pot & 2 bread machine elements which when baking bread actually heat the surrounding air which should work for me. I will also use the ceramic insulators form the BM to hold the element in the pot. I have since drilled/cut/fitted etc the element into the spare pot and done a test run and it looks like a winner. Full current, extreme heat, no smoke etc. Running the element at full and the TO with the pot empty I achieved i> 300 degrees when I shut things down and it was still climbing rapidly with the TO not having cycled off. Took about 5 minutes to reach this temp. I am now waiting on a delivery of high temp ceramic insulation and a few other odds and ends to get this fully operational. I will post further comments and images for anyone who may be interested. My goal is to be able to roast 1200 gram of green to achieve 1KG of brown. Not sure though that the agitation is going to cope with the load. Time will tell.

Steve.

[Mono]

Ok, here are a few images of my latest incarnation and copy of my first 1KG roast profile with it. Minor alterations to happen are a vent to the rear of it, labels for the switches and maybe a coat of paint.

Steve.

[Mono]

A couple more with the exterior casing in place and the 1KG profile

[Koffee_Kosmo]

Well done Mono
Love the way this development has evolved by using a built for purpose dry air element

I once toyed with a custom heat coil design that went up the length of the roast chamber but that meant a special design roast chamber to allow chaff to be expelled without touching the element

Anyway thats got to be the best value 1 kg roaster that actually roasts 1 kg

KK

[Mono]

I was just comparing my original profile for 1KG and the one I posted a couple of days ago and I have managed to reduce roast time by ~ 4 minutes. Have to be happy with that & I didn't use full power.

Steve

[teesquare]

HI!
I have been searching the 'net for a roaster to build…and stumbled across CS. LOVE IT! This is my first post, and - I looked for a "new member introduction section" - but, did not find one on the index page of the forum. If I have overlooked it, my apologies.

@Mono: Is there a complete build thread somewhere on CS that I can follow - to build the unit you have in the pictures above. I am in the USA, and resources for the component may vary slightly…but - I think I can do it with some pictures and, perhaps a few neophyte questions.

I have a Behmor, but - I want more capacity…CHristmas cometh - and friends/relatives have asked for coffee!

Thanks in advance for any guidance you can offer….
T

[chokkidog]

Hi teesquare and welcome to CS!!

Here is the new members thread.

http://coffeesnobs.com.au/off-topic/...o-easy-me.html

Cheers.

[teesquare]

Thanks! Will post there now.
T

[Mono]

Hi teesquare and welcome. No I don't have a build thread, this is as close as it gets. I'm quite happy to answer any questions here or via email/PMs so ask away.

Steve.

PS, still very happy with the results. Roast 1000-1200 grams green consistently.

[teesquare]

O.K...

I found Kosmo's old build on a web site, and printed a copy of that….I will try to wade thru it - and ask for comparisons/contrasts.

I have a Salton popcorn popper base - one that has the built in heat element and sweeper arms. Not a hot air machine. It is the one with a metal shaft. I may build a simple 1 lb. / 500g. machine based on that and a Turbo Oven which is exactly like the ones I see you using in Oz.

But - I really admire what you have made. And, I want o make one for the capacity that it will handle.
Thanks!
T