SC/TO Profiles / Q&A / Tips & Tricks

[ptrmorton]

I bought the motor, delivered, in 2015 for $36.

Zhengk A60KTYZ Ac Synchronous Gear MotorModel: A60KTYZ Motor Body Diameter: 60mm Motor type: AC Synchronous Motor Centric Shaft Gearbox integrated Voltage: 24VAC/110VAC/220VAC Torque: 2.5Kgf.cm~90Kgf.cm Frequency: 50/60Hz Rotating direction: CW/CCW

[ptrmorton]

FYI, my turbo oven was a 1470 watt early Galloping Gourmet. Still works great although it looks pretty grungy. The aluminum spacer is a 3.5 cm wide, meter long measuring ruler from a local hardware store.  Make sure the aluminum is thin enough to bend easily. It is attached to the base about 2/3s of the way around with self tapping screws and is sprung closed.  I used a magic angled stick mentioned earlier in this thread to open and close the spacer.  This is my first gen roaster with cheap ET and BT probes.  The ET probe worked great, but the BT probe could be fussy.  Second gen I upgraded the BT probe to something more substantial (and it was prettier too.... )  Picture of spacer held open by magic stick below.  PM me your email address if you'd like more pictures.

[ptrmorton]

Oh, and be sure you have the spacer open in the direction of your convection ovens rotation to aid with chaff removal.  It is still a mess however....

[David (PalateOfAnAardvark)]

I'm able to roast about 450g in 13 minutes.  The motor will handle more, but I can't get a fast enough temperature ramp up to make for a good roast.  In the summer (Arizona 40 degrees C) I could roast 500g with adequate preheat in less than 14 minutes. 


The roaster is at my neighbors, but I'll stop by later today and get the specs on the motor and take a picture.

I'm a little surprised at the size of your batches. I thought the whole point of the turbo oven was that you could generate enough heat/air to roast larger batches.

Do you set it to a single temperature, let the setup preheat for x minutes, then dump in the beans and let them ride? Or do you change the temp at various time intervals?

[ptrmorton]

Maximum heating capacity is limited by physical laws although some recent roasters designs achieve greater heat transfer efficiencies than an SC/TO. With a 110v source, a 1470 W heater like I have is about the best one can hope for using a household appliance.  This limits my batch size while still achieving a reasonable rate of rise.  With 220v, you can get a lot more bang, but if your heat source is only utilizing 1400 watts, your batch size will also be similarly limited.  It is important to note that there should be a thermal limiter in whatever stirring base you use, so while you may be able to pour in more than 1400 watts of energy at the beginning of the roast, as you move past the drying stage toward 1C, your turbo oven will be doing all the work. If you disable that thermal limiter, I'd be very concerned about burning up the beans, roaster or much, much worse! I never use the heating element in my stirring base past drying stage as controlling the rate of rise is not predictable and energy adjustments during the roast are important to bringing out the best in various beans. Rao's "decreasing rate of rise" mantra is an excellent baseline roast profile, but definitely not a "set it and forget it" endeavor - especially heading into and through 1C. 

[Alaroast]

Peter, any updates on the KKTO?

[ptrmorton]

Peter, any updates on the KKTO?

I bought a Huky, so I sold the KKTO without using it!

[pwest]

The glass on my GG is becoming less and less transparent as the years go by...  I spent some time trying to clean it using a host of different types of cleansers, including some Urnex Cafiza, but made little progress.

How do you guys clean your glass?

Thanks,
Phil

[Ascholten]

Have you tried soaking it in soapy water and using one of those green scrubbie pads?  Often times that gunk is burned on varnish from the bean smoke and oils.
If you can get the glass only, some sodium carbonate,  yes the stuff that is scale remover or coffee pots, that is ALSO pH UP for swimming pools, only a LOT cheaper to buy for pools, might work.  Hot water and let it soak a bit then hit with a scrubbie see if you can get it to come clean.

Have you also tried Rubbing alcohol on a sponge?

aaron

[peter]

Back when I cared to look at the beans... I don't care anymore and roast by temp, smell, and sound... I used an oven cleaner spray and a razor blade.  Spray, let it sit for a minute and the gunk would come off fairly easily.  It was kinda messy, but the glass was crystal clear again, and I never detected any residue afterward. 

The only time I need to see the beans is to make sure they're hit yellow at the end of the drying stage before ramping up the heat, and a quick lift of the lid lets me see w/o losing too much heat.

[pwest]

Peter:
That's exactly why I wanted to get a good look at the beans on Saturday--to get an estimate on the green-to-yellow transition time/temp.  I had only one small spot on my glass where, using a flashlight, I could hope to see it.  I have not tried oven cleaner. 

Aaron:
No: I've not really 'soaked' it because the glass is still attached to the rest of the top and I've been trying to keep that part dry.  In fact, I suspect that all my attempts have been compromised by not using enough water--I should probably get someone to help me and do something like: soak in in about 1" of sudsy water (or however tall the glass part is), and then get someone to lift it up but keep it inverted while I scrub at it from below w/a scotchbrite pad.

I'll take stab at trying these methods this weekend and report my results.

Thanks for the ideas,
Phil

[peter]

If you're only going to clean it every once in a long while, you might think about taking it apart.  You can get the glass entirely separate that way, can clean the flaky gunk out of the interior too (believe me, it does build up in there and could lead to bad air circulation and over-heating, then a dead TO).

But again, lifting the top for a quick peak to check color won't hurt a thing.

Do you use a thermometer of any sort?  That would give you a good idea when it's nearing 'yellow' so that you're only lifting once.  Another thought enters my mind; if you're overall profile is sound and you're not racing from drop to 1C then you'll be in the drying phase for a suitable time and transitioning into yellow correctly, and looking won't be absolutely necessary.

Cheers!

[Ascholten]

I really did NOT want to go here.
I really do NOT want to go here
But HERE we are.

WARNING:  THIS IS DANGEROUS, PROCEED AT YOUR OWN RISK, YOU HAVE BEEN WARNED !!
WHAT YOU DO IS ON  Y O U

For really badly stained trashed glass, Lye works wonders for cutting that crap off.
This is NOT for the feint of hart.  These are industrial strength potentially dangerous chemicals.  If you are not used to working with bad stuff. DO NOT.  do this.

But Lye will cut crap off glass and ceramics like you never seen before.  It will also EAT YOU!   I mean think... it will eat hair out of drain clogs, and turn fat into soap to gurgle away down the sewer.  So what do you think it's gonna do when it hits your hand / arm??

The stuff you put in your coffee pot as 'scale remover'  is super lite, junior, baby lye.  ie a slight alkaline.  Lye is the grand daddy of alkaline solvents.  (within normal people's ability to aquire).

Do know tho, lye will also eat the hell out of metals, especially those lighter in the elemental table like aluminum, so don't dunk the entire thing in there.

Wear gloves if you are going to work with this, and id recommend to be on the safe side, goggles and potentially an apron so if you splash you don't eat holes in your clothes

Aaron

[brianmch]

I also urge caution when using Lye but a little less alarmist than my friend Aaron. He's the admin though so there's liability to contend with!

Safety glasses and rubber gloves for sure, plus the ever present "be mindful" operating state.  My ditzy SO uses it all the time without any trouble. 

[pwest]

If you're only going to clean it every once in a long while, you might think about taking it apart.  You can get the glass entirely separate that way, can clean the flaky gunk out of the interior too (believe me, it does build up in there and could lead to bad air circulation and over-heating, then a dead TO).

I'm not exactly sure when I put this roaster into service, but it was at least 9 years ago--I think this would count as 'once in a long while'... I like the idea of getting the glass off and maybe just dropping it in a tub of Cafeiza for a few hours.  The recirc fan in my turbo oven is making some noise, possibly due to gunk, so cleaning that would be prudent.

Do you use a thermometer of any sort?  That would give you a good idea when it's nearing 'yellow' so that you're only lifting once.  Another thought enters my mind; if you're overall profile is sound and you're not racing from drop to 1C then you'll be in the drying phase for a suitable time and transitioning into yellow correctly, and looking won't be absolutely necessary.

I do have two 2mm TCs: one for ET and one for BT.  Both sampled at a 2Hz rate and brought over to Artisan via WiFi using their Modbus interface.  I've been tweeking profiles, trying to get consistent phase percentages, and to get better consistency and RoR curves lately.

I really did NOT want to go here.
I really do NOT want to go here
But HERE we are.

WARNING:  THIS IS DANGEROUS, PROCEED AT YOUR OWN RISK, YOU HAVE BEEN WARNED !!
WHAT YOU DO IS ON  Y O U

For really badly stained trashed glass, Lye works wonders for cutting that crap off.
This is NOT for the feint of hart.  These are industrial strength potentially dangerous chemicals.  If you are not used to working with bad stuff. DO NOT.  do this.

and

I also urge caution when using Lye but a little less alarmist than my friend Aaron. He's the admin though so there's liability to contend with!

I'm thinking I'll try to remove the glass and soak it in various less potent options.  If that fails, I'll move on to the oven cleaner idea and finally, if necessary, to the lye.  It's good to have options.

Thanks again!
Phil