Differing Meat Temperatures

chuckl

While grilling the turkey on my BGE yesterday using the DigiQ, I ran into something I can’t explain.  I used two meat thermometers, one from the DigiQ and one from a Redi Chek ET-732.  They read significantly different temperatures,  varying from a couple of degrees to +20 degrees on the DigitQ.  I even located the DigitQ right next to the Redi and still got the same temperature difference even though they were inserted to the same depth.

 Afterwards, I put them in a pan of boiling water and they were within a couple of degrees of each other.  I didn’t think of it until afterwards, but I should have checked the temperature with my ThermaPen.

 Anyway, do you have any ideas of why different meat temperature readings?  

Darby_Crenshaw

could be fat pockets, closer to the bone, etc.

even though they were inserted to the dame depth on the thermo, you might have been located in different spots in the meat itself.

@natureboy long ago mentioned the no-brainer trick that helps quite a bit: insert the thermometer until it goes down down down and then starts coming back up again, then pull it out a bit until it returns to the lowest temp.  then leave it alone, you are now in the center of the meat.

most meat tapers in thickness somewhere.  putting two thermometers in to the same depth on the thermometer may be easy enough to see, but one could be actually sticking further through the meat, and closer to the hotter other side

chuckl

Thanks for the reply, I had done what you mentioned in your second paragraph.  It's a little tough to cook meat when there is a 17 degree difference in thermometer readings, that is why I'm spending time on this issue.  Which one do I believe!

lousubcap

Toss one and then there will no hand-wringing Or use the thermapen as the tie breaker.
BTW-welcome aboard and enjoy the journey.

blind99

How involved of an answer do you want?  The easiest answer is to go by Darby's advice above and use a Thermapen.

You're probably never going to get exactly the same measurement from two different thermistor probes set into two different areas, read by two different circuits.  That's the vague, short answer.

A long answer has to do with how you get a temperature from a thermistor probe.  The probe is a resistor that varies by temperature.  The resistance doesn't vary linearly, and every thermistor is a little different. You have to determine the parameters of a probe, then calculate the steinhart-hart equation to get the temp.  Or you generate a lookup table for a probe's values an interpolate each temperature based on the resistance.  You can try to calibrate the probes for freezing and boiling, but that doesn't mean it will also be spot on at every other temp.  And then you switch to a different probe, even with the same model number, and it behaves a little differently.  (I spent a lot of time this summer building temperature monitoring circuits and banging my head over all of this!)

chuckl

Could it be that one of the probes has seen its better day?

Darby_Crenshaw

you tested them and found them to be the same temp in boiling water

pick one thermo and run with it.

it's a lot like pulling your hair out over dome versus grate.

easier to pick one and stick to that

jtcBoynton

chuckl said:

Thanks for the reply, I had done what you mentioned in your second paragraph.  It's a little tough to cook meat when there is a 17 degree difference in thermometer readings, that is why I'm spending time on this issue.  Which one do I believe!

Believe them both. Your boiling water test showed they both are working. The differences you measured are real. I only use a remote probe as a rough guide as to when to start checking with a Thermapen. Use the Thermapen to check several places.

SmokingPiney

jtcBoynton said:

Believe them both. Your boiling water test showed they both are working. The differences you measured are real. I only use a remote probe as a rough guide as to when to start checking with a Thermapen. Use the Thermapen to check several places.

True words to cook by. 

chuckl

I will go with your sage advice.  Thanks

jtcBoynton said:

Believe them both. Your boiling water test showed they both are working. The differences you measured are real. I only use a remote probe as a rough guide as to when to start checking with a Thermapen. Use the Thermapen to check several places.