Behmor 1600: Where to place thermocouple(s)

[ilcaffedio]

My apologies if this has been posted before, but I did search first.
I have found a few different ways to use a thermocouple with a Behmor.  What is the common convention on where to place the thermocouple(s) on a Behmor for use with RoastMaster?

Thanks!

[Danny Hall]

Hello

All of my probe roasting is done on my quest, so any input I'd have is just speculative (I haven't mod'd my Behmor). That being said, I like the placement of this probe http://www.flickr.com/photos/11456365@N03/8728849167. Since there's no way to get a probe directly into the began mass, this looks like it would be a good tradeoff since it's near the bean mass. Looks like it would at least be a good indicator of the heat the beans are receiving, but still a little shielded so as not to be too near the heating elements.

For what it's worth, the ET on my Quest fluctuates a great deal from roast to roast. Now - I roast back-to-back a lot, and the fan variable contributes to this. The Behmor should be more constant than that, but still I think it's worth trying to keep the probe as close to the bean mass as possible.

I'm interested to know how you make out. If you take any pics I would love to see them.

Any questions on probes just let me know.

Danny

[akiley]

My apologies if this has been posted before, but I did search first.
I have found a few different ways to use a thermocouple with a Behmor.  What is the common convention on where to place the thermocouple(s) on a Behmor for use with RoastMaster?

Thanks!

I'm not sure how many people are doing these mods.  They look like a lot of work.  Not sure you saw this one which is actually a bean mass temp for the Behmore.   ... Aaron
http://coffeegeek.com/forums/coffee/homeroast/478368

[Danny Hall]

Pretty tricky!

I have not seen that one before. Definitely an involved process, but very interesting.

[Jerry]

There is really no convenient way to place a thermocouple in the Behmor 1600.  If I were able to thread it into the rotating drum, I would still be concerned about the offset (influence) by proximity to the heaters.

What is possible, however, is to put a thermocouple in the exhaust duct at the top rear of the roaster.

If you have ever removed the exhaust duct (5 screws) you will see that the ventilation air is provided by a small fan.  There is not much air being pushed through;  just enough to keep the roast even and get rid of the moisture.  The exhaust air measurement is in some way analogous to bean-mass temperature but you need to remember that there is a time-delay between the beans and the duct and another in the thermocouple assembly.

I roasted a nice Sumatra this afternoon.  At the point where the second crack was about to begin, I  went to cool.  With no heat being applied and extra ventilation air, there was STILL a temperature spike of 40F.  Roasts really go exothermic …!!  There is real value to be able to see that spike.  The next time I will watch for it and go to cool as soon as it begins.

Roastmaster's data-logging feature is great.  I wonder if there is a way to keep that (manual) temperature graph recording …after... I stop the roast.  I would love to do that to get the full shape of the spike.

Jerry

BTW, the type K thermocouple assembly is high-quality and low-cost and comes with a threaded end and matching nut.  All I did was drill a 5/16 hole at the end of the exhaust duct.  Look here:

http://www.ebay.ca/itm/Thermocouple-K-Type-Probe-Sensors-Connector-50mmL-/250983707501?pt=LH_DefaultDomain_2&hash=item3a6fcb736d

[pablou]

Hi all,

I've installed a iCelsius BBQ probe in my Behmor following some forums.

I'm getting a reading of over 600*F at 1C, it seems to me like a lot.

Was wondering if this is "normal" or if I should move the probe.

Thanks!

[Danny Hall]

Hi pablou

It seems like a lot to me too. Then again, I’ve never mod’ed a Behmor myself. I can say that the BBQ probe is only rated to 484°F, so its worrisome that its reading that high. Perhaps the quartz elements throw out a lot of heat.

Do you have access to a thermocouple, to see if you’re getting a true reading, or if maybe the BBQ probe is faulty instead?

If it’s a true reading, I’d recommend going to a true thermocouple that is rated for that high of a temperature range. The BBQ would not likely last long being exposed to those temps over time.

I’ve built a new probe protocol for the new version of RM called RDP. It’s possible to make a homemade thermocouple host for $50 USD, give or take. But, it would be a DIY project. It’s still new, and there’s no pre-built hardware yet. I have not had a chance to put up any documentation yet. So, let me know if you’re interested in that.

Of course, Phidgets is another alternative, but pricier.

Let me know if you can verify that reading.

Danny

[pablou]

Hi Danny,
Thank you for taking the time.
Inrepeated the roasting with similar settings, and again I got a reading at 1C over 600*F
As a home test, I took temperatures next to the probe before and after with a thermometer, and they snatched.
I would like to learn more about that set you mentioned, as I don't think the ICelsius is going to last long

Thank you,
Pablo

[pablou]

Here's how/where to probe is installed on the side of the Behmor.
I installed it in such way that I didn't need to drill a second whole in the black exterior panel of the Behmor, passing the wire internally through the top.
With this, the probe goes "more inside" than other probes, making it more exposed to the heat elements and air flow, although I may say by a couple of inches.

[Danny Hall]

Ahh, pretty smart!

Sorry, it took me a few days to finish the RDP documentation. It’s complete now… https://rainfroginc.com/documentation/rdp-roastmaster-datagram-protocol
The Probe Host shown in the main photo was built using

1) Feather Huzzah with Wifi SBC ($17 USD)
2) Max 31855 Thermocouple breakout board ($15 USD)

Both of those, along with the breadboard to assemble them, are available from adafruit.com. You’d also need some wiring along with a K type thermocouple. For all parts, I’d expect you’d spend about $50 USD.

If you chose to do this, you could use the Sketch software I’ve already written available at https://github.com/rainfroginc/Roastmaster_RDP_Probe_Host_For_SBCs

Naturally, this is a DIY project. It would require you to build and solder the connections, then download the software to the Feather Huzzah via the Arduino IDE from https://www.arduino.cc/en/main/software

If you decide to do it, let me know and I’ll answer any questions you have along the way.

[Skeens]

Thanks for the sketch software Danny.

[MarkBayerl]

I'm not sure how many people are doing these mods.  They look like a lot of work.  Not sure you saw this one which is actually a bean mass temp for the Behmore.   ... Aaron

I once tried to mod once but really it is a lot of work. But, it does provide you the satisfaction of achieving a goal.

[Danny Hall]

But, it does provide you the satisfaction of achieving a goal.

That has been the sole outcome of some of my machine modding and tweaking ventures. Still worth it in the end, I think!