readeral's KKTO

[readeral]

Here's the photos that were meant to be visible in post #13

[readeral]

A sneak peak of a tantalisingly close to finished KKTO

[Koffee_Kosmo]

A sneak peak of a tantalisingly close to finished KKTO [ATTACH]10553[/ATTACH]

You followed the instructions and recommendations to the letter and you have been rewarded with a well made roaster

Give yourself a few settling in and training roasts and you should be roasting like a pro fairly quickly
Again follow the instructions and tips I have provided and stick to the sweet spot green bean weight I have noted

KK

[readeral]

Another update before I post some things later tonight about what I did with the fire blanket..

So I hit a snag earlier today. The motor would run, and then slow after about 25 second, and eventually (almost) stopped at 30 seconds. I could pull the pots (with some force, as the shaft was sticking in the motor!) and put them back in again, and it would run fine for a further 30 or so seconds and stop. I wasn't sure what it was - so contacted KK, who gave me some suggestions.

The issue was that the drive shaft hole Adifoto and I had made, although happily spinning freely in the workshop with our fingers twirling it, was not wide enough for motor driven use. This was indicated by the little aluminium shards that had begun to accumulate on the underside of the motor and in the walls of my wooden base. I suspect it may have been caking the walls and jamming the shaft, and also falling into the socket where the shaft and motor met, and holding the shaft tightly.

So I pulled it all apart, went at the wooden base with a round file, widening the hole and smoothing it out - put it all back together again, and it's running happily with no problems (cross fingers!) - KK has also asked me to carefully inspect the motor internally for bits - anyone owning a KK motor should contact him about this step.

So - I've learned that there does need to be enough room for the shaft to move and never rub - again another consideration for anyone considering a thicker base.

KKs support and instruction throughout this build has been fantastic - suggestions at every step, feedback on my kooky ideas and recommendations to realign my thoughts.

So later will be update about blanket, and details on first roast.

Al

[readeral]

Ok. Here's the fire blanket update. Images are above so I won't repost them.

I got the fireblanket from Adifoto - he'd used a small part of it in the bottom of his Corretto, so I used the rest. He hadn't used much, but the rest of it was perfect size for me to fold for the height of the roasting outer pot.

I cut off the black tabs, and folded it lengthways, taking the outer quarter in to the middle (like folding bedsheets) and then folded it in half again so it was 1/4 of it's initial width. My wife sewed from the folded edge down to the open bottom 5 times at various points to keep it together.

Next I took a length of baking paper and made a template of the outer pot of my roaster. I cut it to the correct width (the height of the outer pot) and cut one handle hole for one side, attached it and wrapped it around so I could mark the next spot for the next handle, then took it back off and cut that handle hole as well.

After I had created my template, I put it on the stitched blanket, and drew the handle holes onto the blanket. Then I took a permanent marker and marked ~3mm around this rectangle hole. My wife then used a very tight zig-zag stitch to stitch around each marked rectangle. We wanted to to buttonhole stitch, but it wouldn't do it that big. Oh well. Also, the blanket didn't feed through because it's slippery, so needs to be carefully pulled along.

Finally I took to it with a Stanley knife, cut a slip right through the centre of each rectangle (left to right) and ensured that it started and finished 1 cm from each side. From that edge, I then cut right into the corner to make little triangles. So the handle holes were made.

I attached the blanket as you can see in the picture above, with the bottom folded over where there was an additional ~2cm of blanket. We then wrapped the rest of the blanket around, measured how much extra to cut off (with an inch of overlap) did another tight zig-zag stitch and cut it off.

I haven't done this, but will be attaching some velcro, so it can be removed and replaced as necessary (for checking pot centring etc.) - right now it's being held with zip ties. This might be a more permanent option, but I suspect they will loosen over time, because the fire blanket does get warm.

Why did we have the open side of the blanket at the bottom, and fold it over? Because if I want to I could slip in to each slot made by the downward stitches some more insulating material to make the fire blanket more effective during winter. I haven't worked out what that material might be (don't want it to be a heat sink instead!) but I'll keep you posted if I end up doing it.

Any questions just ask me, here's two more pictures so you can see the stitching.

[readeral]

First roast! Would love some feedback and suggestions on how to better my roasts. That being said - it was really quite easy!!!

I followed KKs instructions to "let the roaster do the work"... almost. Couldn't help myself.

I started with 555g of some Brazil coffee (It's all I had left) and let the roaster preheat to 250 degrees. I opened it up and dumped the beans, and let her go!

There were two points that I mucked around with the thermostat (told you I couldn't help myself), and to be honest, I should have just let it go. You can see it in the graph. The second time was right near the end of the roast, I turned it down, and then back up - might have been cause of my issues I'll talk about in a sec.

The motor ran flawlessly - it did increase in it's noise a little bit after about 12 minutes, but nothing worrying.

The one thing that worries me is that I couldn't hear 1st crack at all. Might be because of the beans, I know to expect various different volumes from different beans. Just sucked not to have that on the first roast. I'd intended to push to 7 degrees beyond first crack, but because I didn't know where it happened, I couldn't do that.

So - the roast took 17 mins 30 sec, the total mass at the end of the roast was 475g, so a total mass loss of 15% (give or take for my dodgy scales) - the roast ended up darker than I would have liked (I don't have a CS scale to tell you what it was) but it was definitely a dark roast. No tipping, but maybe a little bit of scorching? Hard to tell. It's fairly even, just darker than I like my beans (and darker than I have seen from local roasters).

Here's a picture of my roast log (using RoastLogger - I have a Mac, which isn't rating high on Andy's carefactor for CS Roast Monitor - but this software works just fine) - you can see the bit at the end where my RoR for the final 2 minutes. I couldn't tell because I forgot to put smoothing on, and so it was a bit all over the place... but post roast I smoothed it out and can clearly see the trend in the wrong direction!

And here's a picture of my beans in my cooler (in natural light at 5pm) you can see there are darker beans consistently through there - a bit too far for my liking.


And here's bonus pics of how I attached my temp probe. It's a 5mm probe, not the CS one, but I'll definitely be buying the 3mm from Andy soon, cause as you can tell from my graph above (and the bottom of my dip on the roast profile) that it's really not a very quick probe...
I grabbed two M3 12mm bolts and nuts, with two spare M5 nuts I had lying around, and two M5 washers, and thread it through the roast chamber wall. Being M3 bolts, no extra drilling required, and with the M5 nuts keeping the thermocouple from slipping, and the washers keeping it in place, it barely moved throughout the whole roast! I could tighten it enough that the thermocouple was not touching right at the bottom of the roast chamber.

[chokkidog]

Hey readeral....those links in post#21 are invalid......

[readeral]

Ah dang it, that's twice I've not been able to post them. They work for me! Not that helpful for other people....

[readeral]

Images for post #21 (in reverse order)

[readeral]

Follow up on the taste of that Brazil roast - after 4-5 days rest, the chocolatey smell coming from the bag was amazing! As espresso very smooth cocoa, in milk, milk chocolate and a little nutty. Quite nice!

I roasted some Kenyan yesterday, very excited to taste it. Unfortunately I had to pull it early. The spring on the thermocouple I have, although happy to wrap over the side of the roaster, does not allow the turbo oven to rest entirely on the silicone tubing. So I'll be changing my thermocouple sooner than I might've intended... as the ramp and roast times I'm really happy with but my problem was that once the Kenyan hit 203, it stalled. I fiddled around with the placement of the TO a little bit and got it to 205, but I had to dump them out, cause I couldn't see it getting any higher. The result still seemed good though, very even roast, nice colour, smelled delicious.


So - the thermocouple over the side would be fine with a TC like the one Andy sells. Has anyone ever tried using a surface mounted TC on the floor of the roasting chamber? I've seen a few screwed to the side, but I'm wondering if it might be easier/more accurate to measure the bean temp from a position that beans are permanently in contact with the TC? Getting a silicone mounted surface thermocouple would allow wrapping the silicone up to slip it through the holes in the inner chamber and place it on the floor of the chamber. Just a thought. I'll think it through some more.

Some other things I'm thinking about:
- Using the aluminium tray mod suggested by nikko.the.scorpio in his thread, on the underside of the glass, to help with those moments when big beans (like the Kenyans!) don't want to push out of first crack, and in general to limit heat loss/allow larger roasts.
- Controlled repeatable way of increasing/decreasing airflow across the roast, either by slightly lifting the TO off the roaster lip with some mechanical process, or adjusting the way it interacts with the silicone tubing.

- long term, it would be great to have some sort of mechanism to allow loading the drum without lifting the TO - but I think that's a long shot, would require welding, and tools and skills that I just do not have.

[nikko.the.scorpio]

Al,

Great build - it looks sensational, works very well and the quality is such that it should serve you for many years to come with scant items periodically replaced. Well done!

Just a couple of very small suggestions:

- I bought one of these from Ebay: 111597898626. Perhaps rather than over the lip of the pot you could go through the base of your outer pot and screw/silicone it into the inner pots base. You'd probably need to drill through your chopping board as well. Alternatively in through the side wall of the pot. Lots of options there, guess it depending if you're after the bean mass temp (which I think is a bit stetchy to accurately gauge) or the internal roaster temp (which is easier to set a friendly probe position with). Lots of probe options out there so just depends which one suits where you're hoping to place it - but your current over the lip one really would cost you a lot of heat loss so I agree you need to change it ASAP.

- As far as the aluminium tray mod to the inside of the roof of the TO. I think it's of marginal benefit so if you do it don't do nuts or too perfectionist about it. I think they say generally 40-50% of the heat is lost through the roof/top of most homes so lets assume this is the same for the oven's environment. When I use one of the uncovered TO lids I can see that the exposed glass that is WITHIN the inner perimeter of the pot is perhaps 20% maximum of the overall surface area - the vast majority being the central section of the TO. So if you say insulation saves 50% of that heat then it's 50% of 20% of 40-50%. So perhaps 5% heat saving available but thats prolly being very generous. But it's easy enough to do so see how you go. Best case I'd say would be reflective insulation like foil on the interior and then insulative stuff on the outside (like some doubled over fire blanket etc). But again I think this is all 'luxury' stuff that really won't make much difference to your end roast.

- I think the opinions on 'burping' the TO to decrease the internal temp are pretty mixed, but lifting the lid off for a set time period would be pretty repeatable in terms of the actual effect it has on the internal temp. So when you combine that with the fact you have a live graphical feed of the internal temp you should be able to get good repeatability. I personally prefer to just drop the TO's temp but either way should work to slow/decrease the temp.

- I see what you're saying about the way to load the beans without opening the TO and you're right I can't see a way to do this without welding or something tricky mechanical. But again I feel this is perhaps complication for little real benefit. As if you're preheating the roaster I don't feel this is a critical part of the roasting cycle were a heat loss (and I find you can dump the beans in very quickly <2sec using an old 2L plastic icecream container that you squeeze to make it angle into a good pouring vessel) is potentially a real issue - like if you stalled it just prior to 1C etc. So I would think you can get better improvements for less hassle improving other aspects of your roaster.

Again your roaster looks great - haha and seriously I think those bigass legs on it really are winners. Special credit to Mrs Readeral for not only sewing one great looking heat blanket mod but also for soldering!!!!

BTW what espresso machine & grinder are you pairing this with? Is this your first forade into home roasting or have you used other methods previously? Great build anyway....I'm very impressed.

PS. Have you loaded up buying green beans for your new toy yet? If so what'd you get or what are you planning on getting?

Wish I could buy more myself as would like a few blenders/base beans but have around 12kg onhand and from what I've read it's best to consume within 12mths and that alone will take me a year to get through (at 500g every fortnight).

[readeral]

Thanks for the kudos and suggestions Nick. Angie has been great with helping me with my build! Marrying an engineer was a great decision. She's been a great sounding board, and helped me understand DC motor theory enough to make decisions around that.


I think from here, any drilling etc. for improvements will be done as major surgery, so any little things would wait till then. That means no probe drilling for now. However with insulated pots and almost 5cm of wood base, through the side would've been my only option.
The probes available through Bean Bay don't have the spring on the end of them, just a cable, which I could easily get over the lip of the pot between my cut silicone tube without causing measurable heat loss, as it'd sit below the thickness of the silicone. The other thing I'm keen for is a 3mm probe, as the 5mm is too slow to respond (I found a graph somewhere that showed the response time of ungrounded thermocouples to their relative diameter, 2mm makes a huge difference!) and Andy's is 3mm.


My biggest concern is not accurate temperature readings per se, but precision. Consistency of environment and predictable repeatability, so, benchmarks that I can hit consistently that give an excellent result in the cup. I'd like to limit as many variables as possible - as the variability of the beans themselves is enough to deal with! I'm sure for most (eg. Ex-coretto users like yourself, ex-popper users like me) the closed environment would seem like a gigantic leap in consistency - and it is! - but having friends that are commercial roasters in Tasmania and talking through theory and practice with them (coupled with my over enthusiastic scientific bent) makes me eager to take what is already a great KKTO design, and find how I can make it as controllable as possible. So in a sense, I'm not fussed whether my probe is measuring bean temps accurately (there's always that person who points out that your probe isn't inside a bean!) but consistently. However, a more sensitive probe (3mm over 5mm) will allow me to see minor changes to the system that would have otherwise been smoothed out by the heat retention of the probe.

I'll definitely be looking at installing an ET probe as soon as I decide if I'm going the TC-4 direction, or another (as my DMM only takes one input).


So, why things like the aluminium shielding appeals is because it may help with mitigating against weather changes. Having a consistent way of loading the beans means limiting ET changes as a result of loading variables (eg. Getting tangled up while pouring in, higher charge weight resulting in taking extra time to get the beans in etc.). Being able to hit my turning point at the same temp every time for my bean profile (once I'm onto a winner), so that my RoR is consistent. Things like that.

Rather than lifting the TO for airflow changes, I thought maybe retrofitting something similar to item no 321574202808 (obviously not this one... but conceptually, think of a hand operated airflow valve with 'stops') to change the airflow might be an interesting thing to think through further. Maybe something for the next 6 months to mull over. I don't pull the trigger on things quickly.

Re pairing with machine
This is not only my first foray into roasting, but my first foray into home espresso at all. I started building this KKTO even before I'd bought my first espresso machine!! I wasn't flying blind though - my neighbour (adifoto) lent me his Silvia for a month while he went home to Romania. My acquiring of a popcorn popper for mucking around with was less than a week before I started committing to the KKTO build, so I can't say I've had much home roasting experience. Done more in the KKTO in the past week than I ever drank from my popper.

My machine, which I've had for about a month, is an ECM Technika IV Profi. I bought it from Jetblack Espresso and they were fantastic. Unfortunately it's paired with a 6 year old Sunbeam Cafe Series grinder, which patiently ground 6 years worth of French Press on the promise of a coffee machine... that never eventuated (bought a freaking expensive drum kit instead...). So all my raving about consistency further up.. yep. The grinder is frustrating me no end. Waiting for someone to sell Super Jolly-E here, or will pick up a Macap M4D in the new year. I've never worked in a cafe, but some of my best friends are baristas and roasters, so you could say that it was an inevitability that I'd succumb to the bug.

So, for cupping my roasts (which I did some of yesterday) I'm using a ceramic Hario grinder, just to ensure I'm able to set a grind setting on a second device that I'll never change. Consistency

Re green beans
Green Beans I've been getting from elsewhere in greater western Sydney, (not Beanbay, despite putting an order in on Beanbay this afternoon...). Cost/kilo is slightly higher, but shipping is lower, and I have the flexibility of buying 1kg lots to get a sense of different beans from different regions. At the moment I have (or have tried):

- Sumatra Lake Tawar
- Colombia Popayan Cauca Supremo (almost all out)
- Brazil 'Toffee' Cerado (all out)
- Indonesia Bunisora Honey processed
- Guatamala Finca Ceylan Organic (all out)

- Brazil Daterra RFA Bruzzi (all out)
- Ethiopia Sidamo Chire Gr1 Natural
- Kenya Kagumo AA

I think I'll be getting a stock of the Brazil Daterra (milk chocolatey, quite delicious), another Colombia, another Guatamala, and I'll decide between the Kenya and Ethiopia which one I want a stock of, probably Kenya as I'd like to get some Ethiopia Harrar Longberry.

[nikko.the.scorpio]

Great post 'Al - well please post any little tweaks you make to your roaster. Understand completely where you're coming from with the controllable consistency etc - absolutely makes sense. Sounds like you're just a matching grinder away from Coffee Nirvana - should pop yourself up a WTB ad as you know it'll drive you nuts if the perfect one comes up but someone beats you to the punch plus you know there's LOADS of folks here just itching to upgrade their gear but too lazy to list them so your ad would be a godsend for them. :-)

[readeral]

Haha thanks. I'm a bit OCD about it. I was just saying to Angie that at the end of all this, I won't have hit the consistency I'm after - but I will have learned a heap. And hopefully will have been able to add back into the R&D that has made the KKTO such an impressive roaster.

Good idea with the WTB - will try to convince the Mrs. It's easier to persuade *ahem* purchase something when being an opportunist :P

I was also thinking re: the aluminium shielding. You really want to avoid any heat returning to the glass, as although the amount of glass in contact with the inside of the system is small, the remaining surface area of the glass with which to transmit that heat into the outside environment is still 500 square cm or so. With aluminium shield, the air trapped between the aluminium and the glass will act as an insulating force as well. Even if one gains 10% efficiency, that's 10% more beans you can get into the roaster with controllable results

What beans have you got in your stash?

[readeral]

Wow just tried my Kenyan as an espresso. Blew my head off with it's brightness! First pour was too fast, so I ditched it (had a bit of a taste, but knew it was bad) - second pour I could smell the fruitiness of it, smelled delicious, and went down quick. Good acidity. Now I get why they say '10% African in blends'.

Needless to say neither my roast, nor my grinder has done this coffee any favours. Hopefully tomorrow it pours even more tastily. Can't wait to have another go at roasting this gem.