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Dogstar

Thermocouple based temp controllers for speed, accuracy and higher cook temps

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So many of the BBQ temp controllers (with a fan, etc.) I've seen out there, are thermistor probe based.  When compared to Type K thermocouple probes, thermistor probes are generally a little slower to respond, less accurate and can't take heat beyond 500 degrees or so. I'm hoping that a step up higher temp thermocouple based BBQ temperature controller might exist?  Are there any options, or does anyone know if this is a "coming attraction" - before too long?

 

 

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Posted (edited)
3 hours ago, Dogstar said:

So many of the BBQ temp controllers (with a fan, etc.) I've seen out there, are thermistor probe based.  When compared to Type K thermocouple probes, thermistor probes are generally a little slower to respond, less accurate and can't take heat beyond 500 degrees or so. I'm hoping that a step up higher temp thermocouple based BBQ temperature controller might exist?  Are there any options, or does anyone know if this is a "coming attraction" - before too long?

 

 

 

I doubt it

 

A temp controller is designed to monitor and run Low and Slow cooks. Probes that will measure High and Fast arent really somthing anyone needs or is asking for.

 

Designing a controller that will measure temps in milliseconds at temps over 500f would mean refining the fan communications to respond as quickly as the probes do in order to take advantage of the speed of measurement 

This also becomes a bit of a "but why, though?" question when you consider charcoal BBQs do not respond to temp changes fast enough to warrent an ultra fast control system

 

The fan assembly would also need a redesign as most components would not be able to take the ambient heat from the grill at high temps.

 

The desire for increased accuracy when it comes to BBQ measuring devices is a strange one. Most good quality leave in temp probes have a rated accuracy of around +/- 3F on cooks over 300f (so around 1%). Getting that accuracy down to 0.5% is not really that much of an advantage in this case. Cheaper probes will be worse, but if youre talking thermocouple based BBQ probes, cheap isnt part of this conversation.

 

Lastly, why would you want a temp controller for cooks over 500F?

Once you're in and around that range, accurate temp measurement and control isnt really an issue as most of what you're cooking isnt going to be in the grill for long enough for an extra 30F-50F to matter much

Theres also the issue that any fire big enough to put out temps over 500f will require more air than a normal sized control fan would be able to produce, so it would need to be bigger/faster (but then it would be hard for it to keep temps low for low and slow cook due to it putting out too much air)

 

TL:DR

Probably not. Any advantages of a Thermocouple based Control system would be offset by the high cost, high complexity and general redundant nature of the advantages found with Thermocouple based temp probes 

Edited by Polar Bear

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After a quick google I found that Thermoworks offer a Thermocouple Based leave in Pit and Meat Probe kit:

https://www.thermoworks.com/ThermaQ-High-Temp-Kit

Now, this isnt a pit controller, but its half of what you were asking about (the easy half)

You'll notice the price on this unit is more than double that of the Thermoworks Smoke and offers no remote viewing of any kind (The Wifi or Bluetooth models are more expensive again)

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Hi Northern Australian Polar Bear:

 

I did find one that says it will do 550 degrees, the BBQube TempMaster.  It comes with "Type T" thermocouples.  The higher heat allowance is probably due the use of thermocouples and the air source being ducted and remote to the BBQ, so the blower can be placed favorably apart from the BBQ which may help to keep the fan assembly cooler, depending on placement.

 

The BBQube looks quite interesting.  The price is good, and it seems reasonably well thought out (the Sous Vide thing is cool).  However, it appears to be bluetooth only device at the moment, and I'd really like to have WiFi so I can monitor anywhere around my house.  I don't know if I care about web access, though I'd take it if they built it in.  Check it out if you haven't seen it:

https://bbqube.us/BBQube-TempMaster-Portable--BBQ-Temperature-Controller-for-Charcoal-GrillsKamado_p_42.html

 

Yes, I posted earlier about those Thermoworks high temp probes and that is a direction I hope they take.  I believe Thermoworks did say they want to have a Thermocouple option at some point.  My post on that topic is here:

https://www.kamadoguru.com/topic/44425-thermometers-instant-read-andor-leave-it-in-multi-probe-wifi-types/?do=findComment&comment=546914

 

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The K-type probe on my Heatermeter registers at least up to 900 degrees. You can find information about Heatermeters at https://store.heatermeter.com/. There have also been discussions on this forum. If you search for "heatermeter" on this site then you will find information as well.

 

Happy cooking

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2 hours ago, Dogstar said:

BBQube TempMaster

@Daz Who actually builds those is a contributor to this forum and can probably comment more on capability.  I don't know why you would worry about controlling temps once you get over 500 on a grill.  I'm basically checking my food every minute or 2 for doneness as it ain't going to be in there for more than a few minutes anyway.  The controller is so I can set a temp of 225 - 275 and go to sleep and not have to worry about the thing until tomorrow.  I have a Qube BTW, the bluetooth is only for monitoring temps and alarms, you can't set the temp of the grill with it, that is still done from the physical device.

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I second the Heatermeter with a thermocouple.  Works a treat.  I routinely use it to hold exactly 400°F when cooking spatchcock chicken.

 

As far as temps over that 400°F range, since i don't use it then I can't really comment.  I do know my Inkbird grate probe did NOT like high temps and I had one case of burnout.


Tom

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On 3/6/2020 at 10:40 AM, Tarnation said:

@Daz Who actually builds those is a contributor to this forum and can probably comment more on capability.  I don't know why you would worry about controlling temps once you get over 500 on a grill.  I'm basically checking my food every minute or 2 for doneness as it ain't going to be in there for more than a few minutes anyway.  The controller is so I can set a temp of 225 - 275 and go to sleep and not have to worry about the thing until tomorrow.  I have a Qube BTW, the bluetooth is only for monitoring temps and alarms, you can't set the temp of the grill with it, that is still done from the physical device.

sorry I was MIA! yes if the grill is over 500 then you better stay close lol. the app is only for monitoring right now. Our probe is designed to go up to 550 degrees. but if you overshoot the reading will go blank but will come back to life after it cools back to under 550.

We've developed the wifi last year but with all this sh*t going on it's getting delayed and delayed for production. we took our time with the app and will provide a totally revamped app next month. 

stay safe and happy grilling everyone!

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My $0.02 worth pay attention to the specs on the probs.> melted one due to the tip having one max temp and the cable another. I also use the heater meter sometime on my long cooks Was experimenting high temp when the thermocouple cable melted. The heater meter was a fun project and easy to assemble it also is a good eye test with the small parts. I use 500 degrees for steaks and i only keep the lid shut for a few minutes. Longer and you run the risk of going from char to charcoal. And at 800 its put pizza on close lid 2 min open and turn 180 degrees and close for 2 min then remove and longer and it starts turning to charcoal.Your high temp is somewhat dependant on charcoal used.

 

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Another operational point on a thermocouple based system.

 

While the thermocouple sensor itself can have wide application range based on the dissimilar metals used in its construction  (i.e. the (range of the probe) a real practical issue in its application comes back to how one gets from the microvolts electrical signal generated by the thermocouple  sensor to a "temperature" reading.

 

 A major consideration for a thermocouple measuring implementation (in the typical measurement applications and also in the case of a controller)  is the reference "cold junction" that the thermocouple output is compared to in order to establish the temperature by way of a comparison math calculation. This reference in a lab setting, for example, was a ice bath.   

 

The details -  https://en.wikipedia.org/wiki/Thermocouple

 

In electronic thermocouple implementations, the reference "cold junction" is a silicon chip equivalent of an ice bath reference  (32 degrees F).  Hence, most thermocouple based thermometers are not functionally accurate below freezing (being designed most often to measure things above freezing (0 degrees C) into very high heat ranges when the measuring unit (and the reference junction) is outside with the probe in the sub-freezing ambient temperatures - as obviously the electronic reference junction physically being at the electronic equivalent of O degrees C (32 F) is outside the design and calibration range.  Think of a reference ice bath being outside in -20 degree F environment when it is supposed to be at 32 degrees.   The probe is fine, its the reference system.

 

I have  controllers that require thermocouple sensor based probes on my outdoor electric oven smoker conversions and on those sub-freezing mornings/days I have to play calibration offset games in the controller settings as the ambient temperature changes over time until the measuring system (i.e , the ambient temperature of the controller unit) gets above freezing.  Same for some of my thermocouple based multi-channel data logging thermometers.  Put the whole thing in the freezer and garbage readings... Put the probe in the freezer and the measurement system in room ambient above 32 degrees and no issues.

 

So if you are planning on the controller for cooks at sub-freezing ambient temperatures for the controller and its internal measurement system, well you do not want a thermocouple based system.

 

 

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