KKTO Help

[Pretzal]

Hi all,

Just looking for some advice on what I'm doing wrong. Virtually all the roasts in my KKTO appear to have inner scorching that I just can't seem to resolve.

It's an arcosteel pasta pot set. The inner roasting volume is 6 litres so would be about 7 litres with the turbo oven on top. It's a rank arena 1400watt oven. I typically roast 600g. Usually I drop the beans in at 200 degrees but the drop temperature doesn't seem to make a difference to the taste. I've tried cold starting the roaster which was probably the worst of all. I've increased batch size to 800g with better results but still a little ashy. Externally the beans look ok its only when they are chewed on that the ashy flavour is revealed and fairly consistently so. I'm stopping the roast usually just on the start of second crack or about 220 degrees. I've started to drop them about 213 degrees and hasn't seemed to have changed the smell or taste.

I've attached the profiles on the graphs to see if anyone has some idea where I'm going wrong or what I can try.

[Dimal]

G'day Pretzal...

Just looked at your roast charts, and they all seem to be a lot faster than most I've seen with KKTO type roasters. It might be due to the TO you've got, 1.4KW is a pretty decent output. Mine for example (and others I've seen), is only 1.2KW....

Try slowing your batch times down somewhat, perhaps aim for a completion time of ~20 minutes, give or take. Also, I'd lower the start Temp. by 10-15C too such that your turn point is closer to 60C rather than above. Have you tried using KK's recommended procedure for when starting out? From cold, add the beans then initiate a 'drying phase' with a low t/stat setting such that the bean mass gets to 100-120C in about 5 minutes, then start the roast proper for a finishing time of an additional 15-20 minutes.

You can try refining your profiles and methods after you've got a few decent roasts under your belt using KK's simple roasting procedure. Works every time, so definitely worth trying out. Paul (KK) did a couple of batches back to back right in front of me, and they were just beautiful in the cup. Out of interest, do you know what the Air Temp. profile is during a roasting session? Your 'Uber TO' can maybe be dialled back a bit if necessary....

Mal.

[Pretzal]

Thanks Mal for the reply,

I'll try the next one with a drop temperature of 175 degrees to see if I can lower the drop temp to 60 degrees. If i then set the thermostat to perhaps 180 for the first 5 min then 230 for the rest of the roast and see how that goes? Am I correct in thinking that the intensity of the heat from the coil is the same no matter what the setting on the thermostat - the thermostat simply controls when it cuts in and out?

Any chance you could post some examples of profiles you've had success with?

[Dimal]

Sorry mate....

Had to give the KKTO away after suffering a few mini-strokes, I just couldn't see or hear anything that was going on. Use a Corretto these days.

Really, given that you've got the CS Roast Monitor running, try to find a setting that gives you a Rate of Rise of ~10.0C/Minute from the end of the Drying Phase and up to the approach of 1st-Crack. As you approach 1st-Crack, you should wind the controller back a bit such that the Rate of Rise settles on about 5.0C/Minute up to the point where you finish the roast, either before, at or slightly past 2nd-Crack. You seem to be achieving this already going by the charts. It's the "ramp" from the start towards 1st-Crack that's giving you all the trouble...

And yes, the T/stat will be just a simple On/Off type that will cycle the element around what ever the T/stat is set to. Depending on whether your TO has an Enclosed element, an Open one or a Quartz Iodine one, will dictate how much the internal temperature will swing around a nominal setting. Again, from your charts, it look to be doing a pretty good job....

Mal.

[Pretzal]

Thanks Mal,

Sorry to hear about your mini-strokes, I did notice your presence missing a while back as you were one of the first people I interacted with on this site. You're very giving with your time, advice and knowledge. Much appreciated.

I had wondered about the ramp up but apart from drop temperature I wasn't sure how I could alter the shape of the profile with only an 'on or off' element. Correct me if I'm wrong, but setting a lower temp on the thermostat isn't going to achieve a flatter profile is it? Not until it reaches temp then it's going to cut in and out. The only way I see this being done is to lift the handle periodically to tame the rise. I can experiment with this but it may be hard to repeat.

I'll have to try this in the coming days. Merry Christmas to you and all

[Dimal]

No worries mate...

The mini-strokes have been happening off and on for a few years now, so kind of know what's coming these days. Appreciate your kind words...

What is often a very worthwhile thing to do, is to do a few dry runs with the KKTO, to get a feel for where different t/stat positions effect the general roast profile.
For example, using dried peas or ceramic baking beads instead of valuable beans, you might find that a t/stat setting of 220C after the drying out phase will lead to a profile that's worth trying out with a batch of beans. It's all a bit suck it and see for the most part, as every DIY Roaster is going to be a bit different but this wouldn't be a bad way to get in the ballpark....

Worth a try anyway...

Mal.

[Pretzal]

Thanks Mal,

The roaster is all good I think from the end of the drying stage I don't have to do anything on 250 from about 150 degrees onwards until first crack where I have to manually lift the handle periodically to maintain a 3-4 degree rise until I stop the roast. My issue will be trying to find a thermostat setting for the start of the roast.

Agreed about wasting valuable beans! It's a great roaster for large batches but not so much if they're large batches of carbon! It brings a tear to my eye when I taste it and it's not nice I've put a big hole in my stash experimenting.

[Pretzal]

I was very keen to try another roast and see if I could tame the first part of the roast. I don't have more than about 500grams of any one type of bean due to the experimenting, so I tried a blend of 50% Kenya AA and 50% Rwanda Nyungwe A. There was some signs of improvement but I'm still not quite there yet. I tried an espresso shot of what I'd just roasted. Initially, it tasted quite nice for about 30 seconds, then I started to taste the ash a tiny bit. It is better, so I think I'm on the right track with larger batches but looking at the outside of some beans and the internals of them there is still some scorching which is what I'm tasting. The roast was quite a bit darker even though it was stopped at the cusp of second crack.

I've attached a profile of the roast vs the first 800gm batch I did. I tried to aim for the 5 minutes to 100-120 degrees and a 60 degree turn point, but it was very manual (lifting the handle periodically below about 130 degrees then left alone) and long term is probably not the best solution, but I was simply trying to prove the concept. Does anyone have any suggestions for settings to try and extend the drying phase without manually messing around with handle etc? These beans are most likely going to take me about a fortnight to consume so might be a good opportunity to re-stock the depleted stash!

Grateful for any assistance to resolve my issue.

[Dimal]

That certainly looks a lot better Pretzal...

Might be worth trying your next batch from cold, which is how most KKTO users use their roasters.
Have you tried getting in touch with KK himself? He is by far and away the best guy to talk to when trying to fine-tune a KKTO. I know it sounds kind of obvious and I'm not trying to 'pass the buck', but KK is a great guy and always seems happy to help out....

Mal.

[Koffee_Kosmo]

The only thing I can suggest is, lower the false floor to increase the volume by 1 litre and give that a try
I assume you also have the agitation under control and checking with the videos I have posted

KK

[Pretzal]

Thanks very much to both of you for the comments.

KK would you suggest trying the 850 gram roast from cold (even through I didn't have much success with the 600gram cold start) as a first step or do you think given my experience so far it would be better to bite the bullet and lower the false floor first?

As far as I can tell I have the agitation under control, but it's not easy to be definitive. Would uploading a video to youtube be sufficient for you to confirm?

[Koffee_Kosmo]

Try lowering the false floor first ( as noted above ) before going any further

I can have a look at your video but if you follow the mixing style in my YouTube videos you should get pretty close
However if you have issues you can email me and I can send you an agitator shape template to use



KK

[Pretzal]

Thanks, I will lower the false floor first. I think I'm pretty close with the agitation as I've used the template for the agitation arms already and the coloured beans seem to indicate reasonable mixing.

Appreciate the advice.

[readeral]

The problem I've found with just going higher with batch weight is although it helps with the start of the roast, you end up with not enough energy output from the Turbo Oven to take your batch beyond first crack, especially if they're denser beans like your Africans, so you bake your beans instead. Lowering the false floor is a much better step, and something I should possibly look at doing too.

[Pretzal]

Hi Readeral,

I don't seem to have too many issues with a lack of energy output, whether it's the 1400 watt Turbo oven or the exhaust wrap around the outside or other factors, a shortage of heat doesn't seem to be my issue. Even with 850 grams, I still have to lift the handle periodically after first crack to tame the rate of rise from about 10-12 degrees down to 3-5.