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

[Tex]

Hi ya all, I am facing the same issues with the thermostat so I decided to install a solid state relay a K type TC and a inexpensive temp controller off ebay. For the fan speed control I am thinking just 2 or 3 position fan switch from goodwill. I have everything I need to set it up maybe tonight I will put it together. It's a blast tinkering with this stuff. I will let you know how things go tomorrow. Rich

I found no advantage to changing the fan speed..  I had my TO heat hooked to a PID but found I was just using it for the temp and could get very good control with the handle on the TO

+1

The TO puts out so much heat that there's no need to vary the fan speed.

I used a gang of PIDs with switches, so I could ramp to various temps and hold there. But  I decided it's just easier to monitor temps using a reliable thermometer and adjust the TO's power output to manage temps.

Be sure to let us know how you make out - it's all interesting to me.

[sea330]

I agree with you 100 percent, adjusting fan speed just complicated my control loop. by removing the thermostat and controlling temps with my TC placed in the beans mass may do the trick of course I will set up my temp controller to control 2 or 3 deg dead band and see how it goes. Just trying different things, maybe I will stumble on something that really works. Oh in my other mod I removed the Teflon from the stir crazy after a few roast the pan started to get well cooked and burned I am sure Teflon will start contaminating the coffee beans, can't be good for ya.   Rich

[RobertL]

Okay I've roasted a few more batches in my sc/to and I have more questions. How long should it take to get the BT to 300F, it usually takes me until about 2:15-2:30. I hold it there for 2:30 and then bring the roast up to 350F. 350F usually is at 7:30-8:00 and 1C happens around 10:30-11:00. Now it seems like everyone else is hitting 1C at 9:00 so I'm guessing it is taking me too long to get to 300F. Also I've always read not to stall the roast so whats the difference in stalling and holding? Does stalling only matter in the temps just before, during and after 1C?

[grinderz]

What's your batch size?

[RobertL]

What's your batch size?

The last two batches I roasted were 10oz but this has been pretty consistent even with 12oz batches.

[J.Jirehs Roaster]

Okay I've roasted a few more batches in my sc/to and I have more questions. How long should it take to get the BT to 300F, it usually takes me until about 2:15-2:30. I hold it there for 2:30 and then bring the roast up to 350F. 350F usually is at 7:30-8:00 and 1C happens around 10:30-11:00. Now it seems like everyone else is hitting 1C at 9:00 so I'm guessing it is taking me too long to get to 300F. Also I've always read not to stall the roast so whats the difference in stalling and holding? Does stalling only matter in the temps just before, during and after 1C?

those numbers sound good to me.. I played around with my preheat temp and found (for my current setup) that a 350F preheat will drop to just under 200F and get back up to 300F at about 3 minutes..  (it depends on the bean.. WP or DP older, newer.. ) I think my TO is getting old so a newer one may need a lower preheat temp..

[peter]

1C happens around 10:30-11:00. Now it seems like everyone else is hitting 1C at 9:00 so I'm guessing it is taking me too long to get to 300F.

You're in the right ballpark, and I wouldn't say you're too slow.

Also I've always read not to stall the roast so whats the difference in stalling and holding? Does stalling only matter in the temps just before, during and after 1C?

Stalling and holding are the same thing.  Stalling during 1st is the worst (I'm a poet, but don't know it)     There should always be a small/steady increase in bean temp.  I'd remember why, but it's late and my brain is tired.  Something about chemical reactions, and the reactions you want won't happen if it stalls.  IMHO stalls aren't as bad temperature drops.

[grinderz]

Buttwhiskers, we need you!!!

[farmroast]

Okay I've roasted a few more batches in my sc/to and I have more questions. How long should it take to get the BT to 300F, it usually takes me until about 2:15-2:30. I hold it there for 2:30 and then bring the roast up to 350F. 350F usually is at 7:30-8:00 and 1C happens around 10:30-11:00. Now it seems like everyone else is hitting 1C at 9:00 so I'm guessing it is taking me too long to get to 300F. Also I've always read not to stall the roast so whats the difference in stalling and holding? Does stalling only matter in the temps just before, during and after 1C?

Interesting starting approach. After your pre-heat you must be going pretty much pedal to the metal til you get to 300f BT and are then doing a hold. My TO roaster is a bit different with high speed agitation and use a different approach. I pre-heat to a similar level but then use less than full heat to get to 300f BT at approx. 4:15-5:00 for the average harder bean. at this point my BT RoR is approx 23-26 degrees/min. I then increase heat to keep about that rate which will then naturally start to slow around 360 BT. when I hit the MET I've found safe for my setup and the beans I'm roasting. I'll then stabilize that MET as the roast heads to 1st. The roast will naturally slow. At start of 1st my BT RoR is somewhere around 11-14/min. 1st  starting around 9:30-10:15. Then adjust my temp. and RoR to the desired finish for roast level and brew method.

[Tex]

Okay I've roasted a few more batches in my sc/to and I have more questions. How long should it take to get the BT to 300F, it usually takes me until about 2:15-2:30. I hold it there for 2:30 and then bring the roast up to 350F. 350F usually is at 7:30-8:00 and 1C happens around 10:30-11:00. Now it seems like everyone else is hitting 1C at 9:00 so I'm guessing it is taking me too long to get to 300F. Also I've always read not to stall the roast so whats the difference in stalling and holding? Does stalling only matter in the temps just before, during and after 1C?

Interesting starting approach. After your pre-heat you must be going pretty much pedal to the metal til you get to 300f BT and are then doing a hold. My TO roaster is a bit different with high speed agitation and use a different approach. I pre-heat to a similar level but then use less than full heat to get to 300f BT at approx. 4:15-5:00 for the average harder bean. at this point my BT RoR is approx 23-26 degrees/min. I then increase heat to keep about that rate which will then naturally start to slow around 360 BT. when I hit the MET I've found safe for my setup and the beans I'm roasting. I'll then stabilize that MET as the roast heads to 1st. The roast will naturally slow. At start of 1st my BT RoR is somewhere around 11-14/min. 1st  starting around 9:30-10:15. Then adjust my temp. and RoR to the desired finish for roast level and brew method.

Agreed! I never use 100% power other than to preheat.

It swings from 85% to 60%, then back up to 80% to 60%, then 85% to zero; then back to 80%.

That translates to ~3 mins to 300°, then slow down for a minute; a minute or so to 370°, then slow down for 2 minutes; a minute or two to 1C, then power off & coast through 1C on exothermic heat; slow climb to  2C and counting - thousand-one, thousand-two...

[peter]

Agreed! I never use 100% power other than to preheat.

It swings from 85% to 60%, then back up to 80% to 60%, then 85% to zero; then back to 80%.

That translates to ~3 mins to 300°, then slow down for a minute; a minute or so to 370°, then slow down for 2 minutes; a minute or two to 1C, then power off & coast through 1C on exothermic heat; slow climb to  2C and counting - thousand-one, thousand-two...

Have you ever timed your roasts?  A minute from 300 to 370 seems very fast, even if you add in the "or so."  Same goes for 370 to 1st.  A minute or so?

Let me suggest lowering your heat just as you're heading into 1st, so that you don't have to coast through 1st on the exothermic heat.  From what I've read (don't ask where) you'll bet better chemical reactions if the bean doesn't have to supply the heat to produce the reactions.  Should be an easy thing for you with the router control.

[blzrfn]

Yeah those numbers, be they ET or BT, seem a little off to me as well.  Of course roasting in Texas may require a whole lot less heat input to change BT than it does here in the PacNW.  Tex, maybe you could make a vid of your roasts like you did for the vacpot and zoom in while you're staring at the clock.

[RobertL]

I just got my router speed controller in yesterday so I will be able to adjust the power now. I'm out of town on a mini vacation for the weekend but when I get home I'm going to do a few experimental roast. Thanks for all the replies.

[Tex]

OK, those were just approximate numbers - I don't give away all my tricks for free!

[Tex]

I just got my router speed controller in yesterday so I will be able to adjust the power now. I'm out of town on a mini vacation for the weekend but when I get home I'm going to do a few experimental roast. Thanks for all the replies.

I've wired my CO so the fan & element are split - it's full speed at all times for the fan. The router speed control feeds into the Kill A Watt, which feeds into the element.  Fry's has a convenient 1' extension cord for connecting the KAW to the speed controller (my controller's plug is buried).

After preheating & dropping the beans, I shoot for ~105VAC to 300°F. From there you can play it by ear until you find a profile you like. The trick is to listen for the outliers of 1C, then cut the power until 1C is done, then roll the power back on.