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Struja

Holy Temperature Confusion!

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I just got my Flame Boss 400 temperature controller (which is amazing) and meant to help stabilize my KJ.  It comes equipped with an alligator clip to monitor ambient temperature, which I attached to the dome thermometer.

 

About six weeks ago I tested my dome thermometer and it seemed to be working spot on..

 

Today I did a boneless Prime Rib Roast.  The plan was to do it at 375.  Unfortunately, I couldn’t get the FB working properly until I did a firmware upgrade which was about an hour into the cook.  
 

Before I got the FB going, I was using my Meater+ wireless probe to monitor both internal and ambient temps of the Roast.  Eventually I got the FB working and so starts my dilemma...

 

The FB ambient probe was reading 389 at one point, while the dome was at 360 and the Meater+ was at 333.  Three ambient probes, 3 different temp, with almost a 60 degree swing.  The FB and the dome were in the same exact spot and the Meater+ was pretty darn close.  Too make things more fun, the Meater+ probe had the internal temp 20 degrees hotter than the FB meat probe.  This one wasn’t as big a deal because I used my instant read to find the Meater+ was wrong.

 

Ultimately, the roast came out great but I am so confused.  Any thoughts?  Should I just give up on the Meater+ probe?

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Don't get so OCD with the temperatures.  Use the flameboss and put the ambient on the grate.  Close the upper vent to about 1/16 of an inch and let her run. Temps will drive you crazy and it's not necessary. 

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12 hours ago, just4fn said:

Don't get so OCD with the temperatures.  Use the flameboss and put the ambient on the grate.  Close the upper vent to about 1/16 of an inch and let her run. Temps will drive you crazy and it's not necessary. 

 

I would be very upset at having 2 quite expensive temperature tools measuring so far apart from one another.

 

I think that is the real point here, but I could be wrong.

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1 hour ago, Rick in Ontario said:

 

I would be very upset at having 2 quite expensive temperature tools measuring so far apart from one another.

 

I think that is the real point here, but I could be wrong.

Exactly!!!  The Meater+ probe wasn't my choice, it was purchased for me by my brother-in-law, so at least I didn't have the expense.

 

The Flame Boss, however was just purchased for $299 CAD + HST (almost $340 CAD). 

 

The two devices could not have been more than 2-3 inches from one another, but I went to the Meater website and they have an explanation for why the Meater probe might have been reading on the low side...

 

1.  What they call a "cold bubble".  Because the Meater probe is half in the meat and the top half which measures ambient temp is half outside the meat, a "cold bubble" can be created over the probe, leading to colder temperature readings.

 

2.  I placed the probe on top fo the roast, smack in the middle of the roast, meaning the entire roast was acting as a temperature shield, which may have lowered the reading.  I think this one is an easy fix by simply adding the probe through the side of the roast.

 

The bigger issue I was really concerned about was the reading off the FB and the KJ dome probe.  The FB probe was clipped to the KJ dome probe, so presumably they should have been reading the same or at least close.  They weren't and that was the one that was giving me pause for concern.

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I could see the dial dome probes and electronic controllers being off by a significant, ummm, degree. Odd that the 2 electronic controllers were 10% off from each other, if I read the original post correctly. 
 

While confusing, our cooks are generally very forgiving. We’re mostly not making soufflés or meth, so temps being off or swinging by a moderate amount, i.e. not running away and not crashing, should probably not greatly affect the cook other than lengthening or shortening the time. 
 

 

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1 minute ago, Chris Topher said:

I could see the dial dome probes and electronic controllers being off by a significant, ummm, degree. Odd that the 2 electronic controllers were 10% off from each other, if I read the original post correctly. 
 

While confusing, our cooks are generally very forgiving. We’re mostly not making soufflés or meth, so temps being off or swinging by a moderate amount, i.e. not running away and not crashing, should probably not greatly affect the cook other than lengthening or shortening the time. 
 

 

Yes, this was very true for this cook.  The end result is that we had a very nicely piece of Prime Rib that everyone in the family enjoyed.  The middle was at medium rare to Medium and the outer ends were Medium to Medium well (which is how wifey likes it).  

 

Since I am new to Kamado cooking, I know that I am WAY over thinking this, because it ultimatelyd didn't effect the final result and I think the thread @John Setzler linked to above sort of reinforces that point.  

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You can re calibrate the dome thermometer. Unscrew it from the KJ and place the probe in a pan of water and check the temp (212f/100c). There is a small screw on the rear to adjust. Whilst you are at it put the FB temp probe in the pan as well so you know if there is an offset which should be no more than +/- 1.5F:

 

Unlike the majority of controllers on the market, Flame Boss probes are not thermocouples. They are platinum RTD sensors and are very accurate. More info here: 

http://www.nakedwhiz.com/productreviews/flameboss300/flameboss300-2.htm

 

My KJ dome thermometer read differently (it was wrong) from the FB. I follow the rule that when cooking with the FB in place I go by its temp. When cooking without I use the calibrated dome thermo as a guide. 

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3 hours ago, Chris Topher said:

We’re mostly not making soufflés or meth, so temps being off or swinging by a moderate amount, i.e. not running away and not crashing, should probably not greatly affect the cook other than lengthening or shortening the time. 
 

 


not that I’ve cooked a soufflé or meth, just for the record :) 

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20 hours ago, Heuer said:

You can re calibrate the dome thermometer. Unscrew it from the KJ and place the probe in a pan of water and check the temp (212f/100c). There is a small screw on the rear to adjust. Whilst you are at it put the FB temp probe in the pan as well so you know if there is an offset which should be no more than +/- 1.5F:

 

Unlike the majority of controllers on the market, Flame Boss probes are not thermocouples. They are platinum RTD sensors and are very accurate. More info here: 

http://www.nakedwhiz.com/productreviews/flameboss300/flameboss300-2.htm

 

My KJ dome thermometer read differently (it was wrong) from the FB. I follow the rule that when cooking with the FB in place I go by its temp. When cooking without I use the calibrated dome thermo as a guide. 

 

If it was me I would be comparing all 3 units in the boiling water.

 

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22 hours ago, Heuer said:

You can re calibrate the dome thermometer. Unscrew it from the KJ and place the probe in a pan of water and check the temp (212f/100c). There is a small screw on the rear to adjust. Whilst you are at it put the FB temp probe in the pan as well so you know if there is an offset which should be no more than +/- 1.5F:

 

Unlike the majority of controllers on the market, Flame Boss probes are not thermocouples. They are platinum RTD sensors and are very accurate. More info here: 

http://www.nakedwhiz.com/productreviews/flameboss300/flameboss300-2.htm

 

My KJ dome thermometer read differently (it was wrong) from the FB. I follow the rule that when cooking with the FB in place I go by its temp. When cooking without I use the calibrated dome thermo as a guide. 

In my original post, I may not have been clear, but before getting my KJ, I remember watching an online video comparing it to the BGE and one of the things that they said was that the dome thermometer was way off.  Within 2 weeks of getting mine, I removed it and tested it as per the video above and I did not need to adjust it because it was spot-on (which is also why it concerned me).

 

I think I should probably do it again though because a few weeks back, I had the dome thermometer pierce some food and foil when I was smoking some ribs on the expander rack.  I will get it a try this weekend (and maybe do what @Rick in Ontario says - and test them all).  

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On 11/3/2019 at 5:14 PM, Struja said:

The FB ambient probe was reading 389 at one point, while the dome was at 360 and the Meater+ was at 333.  Three ambient probes, 3 different temp, with almost a 60 degree swing.  The FB and the dome were in the same exact spot and the Meater+ was pretty darn close.  

Without seeing, I can't say anything, except...

 

This is normal in my use of thermometers. But there's a reason... 

 

I try to put one probe in the coldest spot, and one in the hottest spot under the dome, so I know what sort of range of temps exist, and because the hot-cold difference is useful in controlling the dome temperature. The only time everything reads close is the end of a long cook. The dome thermometer rules the cook, the remote probes serve to control it. 

 

Have fun,

Frank

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