A bullet smoker question

[Deeez]

Hi All,
I had an interesting thing happen last night. On a 22" bullet smoker ... I used both grates, water pan (no water). I just put some gaskets on the lip of the lid. So now that the fire started, the lower grate heat is 30f degrees higher than the the top grate through the cooked and then about 3qtr into the cook, it crept up closing the gap to about 15-20f. Usually for me, the top grate gets hotter than the lower one.
Has anyone experienced this or know why this happened? I'm thinking the probe was right under a bunch of bellies I was doing on the top grate, but then, why the creep up of temps all of a sudden. I tested the probes and the all seem to be in sync.
Thanks ahead for any insight on this.

 

[Chasdev]

I used to obsess over cook chamber temps. At one time I ran 6 digital probes during brisket cooks to try to nail down what exactly was happening from beginning to end of a long cook.
I never did figure out why the temps were where they were but I did observe that cold meat really messes up a perfectly even temp cook chamber and that where the probes are placed has a major roll in the data they report AND that the data changes on each probe quite a bit from the beginning to the end of the cook.
I also learned from reading a few million posts on this subject that small differences make no difference, it's the averages that you should aim for and monitor, so 30 degrees is nothing to worry about on the grand scale of things.

 

[smokerjim]

Maybe the probes were to close to the cold meat and as the meat heated up the temps got closer.

 

[Deeez]

I used to obsess over cook chamber temps. At one time I ran 6 digital probes during brisket cooks to try to nail down what exactly was happening from beginning to end of a long cook.
I never did figure out why the temps were where they were but I did observe that cold meat really messes up a perfectly even temp cook chamber and that where the probes are placed has a major roll in the data they report AND that the data changes on each probe quite a bit from the beginning to the end of the cook.
I also learned from reading a few million posts on this subject that small differences make no difference, it's the averages that you should aim for and monitor, so 30 degrees is nothing to worry about on the grand scale of things.

Chasdev , got it thanks for the input. Yeah, its quite confusing, but will try it again in a few days and let everyone here know how it went. This is the first this happened.
smokerjim , yeah thats what I was thinking, so more testing for me to do. Thank you both for your replies.