Best way to get accurate therm readout of grill?

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Fire Starter
Original poster
Jan 20, 2014
I have a GMG Davy Crockett. I did some chicken breasts today. Entire time, the smoker temp was showing 275 while my thermometer I had in the smoker was showing 250-255. Both fluctuated a bit but it was always a 20-25 degree difference.

After I took all meat off, I let it keep going. Thermometer in the same spot. Hanging down about halfway in the center of the grill. They are now both reading within 5 degrees of each other consistently. So both are working correctly. I did test the one I have in there yesterday in boiling water and it was at 211.

So with no meat on the smoker, both are reading about the same. With meat in, the external probe is reading 20 degrees below the smoker probe. Would cold meat in there for 2 hours make it read that much different? Where would be a better placement to get an accurate reading?
Ya got a lesson in physics.

Cold meat is a heat sink. It absorbs available heat, like a sponge absorbs water. If the smoker was reading 275°F before adding the meat, and 250°F after adding the meat, the fire hasn't cooled off. Chamber heat is flowing into the meat. It's physics.

Chicken breasts are done at a relatively low temp, like 160-165°F. Pork butts are finished at a higher temp, like 200-210°F. Which takes us to the second physics lesson.

Heat is absorbed by meat at a rate determined by the temperature difference between the meat and the chamber. Big difference, like the beginning of a smoke, heat is absorbed quickly. As the meat temp rises, heat is absorbed more slowly. Chemistry aside, that's why many of us crank the heat up after the stall so the meat will absorb more heat per unit of time. A pork butt in a 225°F smoker can take hours upon hours upon hours after the stall to rise to a finishing temp where the meat is probe tender.

Test on Friday.

Great response. Much appreciated. So if there will be a 25 degree difference when meat is in there, which thermometer should I go off of?

I have my meat probe always, so I know what the meat is at. But if built in smoker therm is reading at 275 and external smoker therm is reading at 250 because it’s closer to meat (which the built in one also is close to meat), which one should I use to determine what to set it at?
The one farthest from the meat. If you make changes based on the one closest to the meat, you'll run hotter than intended. As the meat warms, the higher chamber temp will become obvious and you could end up chasing a desired temp.
Only thing I can add is in my MES units, I found about 3" from the meat a good place for the Digital External Therm sensor. This would be beside or below the Meat you want to control.
That seems to be far enough from the meat to not let the Cold of the newly introduced meat to effect the Therm, yet close enough to the Meat to tell you what the Temp is in that "part" of the smoker.
This is the main reason the External Therm is more accurate than any built in.
The one you put in the area of the Meat you want to track, and the Built in is Fixed & only measures the temp in that immediate area.

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