WSM top and bottom grate heat direction, fat side up/down

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Fire Starter
Original poster
Aug 17, 2011
Shedd, OR
Assuming one wants to put a brisket's fat side towards the heat, the preponderance of opinion suggests the heat direction for the upper WSM grate is from the bottom, but for the lower WSM grate just over the pan of water, does the heat still come from the bottom, or does the heat come up and around the water pan and swirl down on the top of the brisket?

With a brisket on each WSM grate, one of my flats came out a little dry. Between my tending actions and notes, I can't put a finger on why the one flat was dry.


The lower grate was the dry one. Bet cha. It was undercooked because it so close to the water, and thus cooked at a lower temp than the higher grate.

Water is a heat sink that cannot get hotter than 212F at sea level, lower temps at higher elevations. The upper grate, further from the water, mixes with more hot air from the fire. It will run 15-25F hotter than the lower grate.

Stop cooking water and learn to control temps with your vents. There's still a small difference in grate temps, but not as much as with water.

3 gallons of water weighs almost 25 lbs and has a higher heat capacity than meat. That means it absorbs more heat per unit of time than the meat does. If you have two 10 lb hunks of meat and 25 lbs of water, you're cooking 45 lbs of mass, consuming more fuel and wasting available heat on water instead of meat.

Anyway, that's why one came out dry (underdone) and the other was fine.
What Ray said... so eloquently .
Stop cooking water and learn to control temps with your vents. There's still a small difference in grate temps, but not as much as with water.
I use a 1/4" steel disc that I cut to the diameter of the bowl. Works great.

Your chuckle for the day Ray....

Also clay saucer works great. Wrap in foil sit on top water pan. Easy cleanup to.

Here a image from someone else.


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Thanks for the replies.

My upper-rack brisket was 12-lbs trimmed fat-up and pulled at 9h10m with internal temps of 203-210F. The flat non-fat-side was dry and leathery/desiccated looking.

My lower-rack brisket was 13-lbs trimmed fat-down and pulled at 9h50m with internal temps of 204-209F. The flat was moist.

In both cases, the WSM top-grate held at 244-268F (the lid at 245-265), and I paper/tallow wrapped at 6hours with internal point temps of 171-174, and one flat temp of 160F (I failed to probe the other flat, stupid me).

I feel like I'm getting good temp control, and I know using water is debated, but taking one step at a time I'm trying to figure out why the upper-rack brisket got scorched on the bottom, and if I should go fat side down next time. I'm also trying to validate that fat side down on the bottom rack was the right call.

Lots of learning, and I don't want to read too much into any one smoker session.


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