18" WSM Top Grate vs Bottom Grate Temps

[klflowers]

Saturday night I did (2) 8lb butts on the WSM for a church function on Sunday (sorry, no pics this time). I set it up like I usually do, filled the charcoal ring, a couple of chunks of apple wood and a full chimney of lit coals. Since I was doing 2 rather large (for me) butts, I used both racks. I also broke out the brand new Mavrerick XR50. Filled the water pan with hot water and got things going. I put a probe on the top grate, and when it got up to around 240 I put the probe on the lower grate, got the probes in the meat and loaded her up. Imagine my shock when I looked at the temps and the bottom grate was reading 50 degrees cooler that the top grate! I never cook with both grates since I only cook for a few people at a time on the WSM, so it freaked me out! I quickly figured out it was because of the water in the pan, and I didn't do anything rash. Eventually, around 2 1/2 to 3 hours in, the temps came together and the difference settled down to around a 10 degree delta.

Since I had to work Sunday, I pulled them at around 1AM (they were at 160 and 155; I put them on at around 6:30 Sat and I rotated them 4 hours in) and wrapped and finished them in the oven at 225. Took them out around 9AM, cambroed them, pulled them at noon and delivered to the church. I didn't get to stay for the event, but all the reviews were positive. Of course, I held some back, and it was pretty good.

Moral of the story - boil the water! Hot tap water just won't cut it.

[EdF]

I just don't use water anymore, but different cookers need different treatments. Glad you got to keep some at home and enjoy!

[klflowers]

Thanks, EdF. I keep saying I am going to skip the water, but it is a habit.

[Troutman]

I agree with my esteemed colleague, I ditched the water pan altogether in my WSMs. I find with having a fan control things it just works much better. If I need moisture I just put a little pan of water on the grate next to the meat.

[Spinaker]

Glad to hear everything worked out, it sounds like it was a hit!

Have you tired not using any water? When ever I have cooked with a WSM, I always leave the water out. I have a friend that never uses water in his. The empty bowl will still block the direct heat, but you don't have the water steaming off into he cook chamber.

[klflowers]

It turned out pretty good. Bark was not excellent, but the meat tasted great. Got to try leaving the water pan empty.

[jfmorris]

Heck - I get a 50 degree delta from the cooking grate on my 22" Weber Performer to the dome thermometer, and that's closer together I imagine than your grates are, so I am not surprised. I only see the temperatures come close together on really long cooks when I don't touch the vents or open the lid.

[holehogg]

My vertical gassers cook chamber from lowest rack to top rack about 35 inches has a temp swing of 25 to 30C when lightly loaded and 15 to 20 with bigger loads. If memory serves the difference was even more when I did a dry run.

[Hulagn1971]

I no longer use the water pan in my WSM either. I just cover it with foil and roll with it.

[JeffJ]

Wow. I'm surprised by the temperature difference. In my 14.5 I've noticed almost no difference to a point where I don't even bother measuring temps at the grate any more. I just poke the probe through the grommet and measure temps halfway between both grates. I only fill the water bowl about 1/3 of the way. This enables me to run my vents pretty much wide open during the first couple of hours of the cook which improves airflow to the wood (cleaner smoke). Once the water evaporates I close the top vent most of the way and it settles in at a steady temp - usually in the 260 range.

[klflowers]

I fill the water pan all the way up. This is the first time in a long while that I have cooked on both grates, and the first time with fancy temp monitoring equip. I cook on the top grate all the time and I have the temps and vent positions down for that. I like the idea of just poking the probe through the grommet and measuring the temp there.