Top Grate Hotter than Lid Temp?


 
A

Andy Erickson

TVWBB Pro
I just got the new 2009 18.5 inch WSM for Christmas. Last weekend I did a brisket on the bottom and butt on the top and it turned out great. However, during the cook the top grate temperature was about 15 degrees hotter than the lid temp during the entire cook.

I just figured one of the thermometers were off, but I just tested all of the thermometers that I own and they all checked out to within one or two degrees. Here are my results:

Weber Lid Therm - 212 (Boiling Water) and couldn't read the ice water because it doesn't go that low; Maverick ET73 Smoker Probe - 212 and 34; Maverick ET73 Food Probe - 213 and 35; and Accurite Intant read - 211 and 32.

I used the minion method with a full ring of charcoal and started with about 20 lit on top. I then filled the water pan with hot water let it go overnight. I also put the smoker probe as close to the middle of the grate as possible. Do you hang it upside down or do you put it on top of the grate?

Just trying to figure out why this happened. The food turned out great by the way.
 
Andy,

I had a post on this site (you can seach for it) years ago where I had the same issue your refering to. I have found until the cooker really settles in the meat may cause a difference in lid temp vs grate temp. I have also found that 3" off the center of the handle is ideal for mounting a thermo.
 
I'm sure weber put the vent in it's location for a reason ... I read something on komodo/kamado how they moved the vent off center to stabilize cooker temp and move the swirl to the lid ... maybe it's the same with WSM.

I don't trust my top vent temps when it's breezey but otherwise it works ok for me.

When I was using the ET-73 I would try to keep the inside probe an inch or better inside the water pan edge vertical ... and an inch or better (this doesn't always work out) from large hunks of cold meat.

Did your ET-73 come with a grate clip? Don't mount it below, posistion it where liquid won't enter it in any way. If you angle it do it point end up so liquid won't accumulate on the wire end and possibly enter it.

I guess the short of it is if your therms are all correct, they are correct.
 
Also keep in mind that the more meat you load into the WSM, the more the airflow is blocked. If you get too much meat in there, or too big of a pan, it can block airflow enough that you get all bottom heat and very little top heat. That can cause huge differences in grate verses lid temps.
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That makes sense Bryan. I think next time I do a brisket and butt I will measure at the bottom and top grate and top vent to see the differences. If there was a 15 degree difference between top grate and lid, then who knows what the difference was between top and bottom grate.
 
Just a quick update:

This last Saturday I did 3 racks of ribs on the top grate and a fattie on the bottom. During the first 3 hours or so of cooking the lid temp was constantly higher than the top grate temp. But after that it seemed to stabilize and went back to the top grate being about 10 degrees hotter than the lid temp. Even after I pulled all the meat off the WSM I continued to monitor the temps for about 2 hours and sure enough the top grate was still about 10 degrees hotter than the lid temp.
 
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