Wanted to resurrect this thread because I had a Maverick temp issue during my brisket cook last weekend. I'm using a 22.5 in kettle..
So... I waited until my temp was stable at 240 before putting the meat on. Got the brisket on, temp came back to 240 shortly and I thought I was sitting pretty. Then I noticed the meat temp was shooting up way too fast. It went from 55 to over 100 in the first 2 hours. I went out and took a look at my dome temp ( I have a Weber Performer).
I know these are not accurate, but my dome temp was reading around 140 deg higher than the grate temp. That combined with the skyrocketing meat temp got me nervous. I ended up cooking at grate temp 190-200 for a few hours and ended up being ok in the end.
The strange thing is, about halfway through the cook, I repositioned the meat around and moved the Maverick grate probe to a different part of the grill. From that point forward the Weber dome therm and the grate temp were about 30 deg apart.
So could this have something to do with where I placed the probe at first? I'm thinking maybe it was cornered in some cold spot or something on the grate? The brisket was very large and I had to position in diagonal across the grate. I had the probe on the opposite side from the heat source. Could this be the problem?
Edited to add: After my cook I put both probes in boiling water and they read 212 exactly.