Originally Posted by IamMadMan
The basic law of thermaldynamics is, heat is exchanged (absorbed) quicker than cold...
Huh? I've heard of the heat transfer by conduction, convection and radiation but I've never heard of cold transfer via any of those means. Can you explain?
To the OP, I just put 4 good sized butts, just out of the fridge, into a 275 degree WSM with the water pan about 2/3 full (cooker had been at temp for 25-30 min). The temp dropped to around 210. I don't have time for a real slow cook today so to get the cooker back up to temp I cracked the lid, rather than add more coals. The temp came back up to 275 in 10-15 minutes and I was good to go from there.
I think you have a couple of things going on that are contributing to the drop in temp and then the need to close the vents down a little after adding more coals. I find that lump charcoal reacts to changes in heat load (the meat going in) and air supply more quickly than briquettes. The same is true when using the terra cotta pot base instead of the water pan. The pot base is not as good a heat sink as the water pan, and it doesn't have near the thermal mass. You're going to see more, and faster, temp fluctuation with the saucer vs the pan.
Originally Posted by souroull
There was only some 3-4lb of lump in there for a clay saucer test, and trust me, last time i tested with a proper load i couldnt keep it under 300 while empty no matter what i did with the vents:)
I find that my WSM does not like to have less than 2/3 full charcoal ring to start. I see in a previous post of yours that you had used some leftover charcoal from a previous cook. I never do that. I tried it and got nothing but unpredictable results. Charcoal is cheap enough to use fresh stuff every time out.
Also, how did you light the coals? Are you using the Minion method or are you following the directions that came with the cooker? The amount of charcoal you have in the cooker should have no bearing on the temp it will run at. It all depends on how much of that charcoal is burning at once.
One other thing about the WSM, don't worry about air leaks. If you make sure that the door fits halfway decent and the center section is round (which is easily coaxed into shape if didn't come that way), the gaps at the bowl and the lid will not be a problem. They will not contribute to temp fluctuation in any way. I guess what I'm saying is that you can probably ditch the foil gasket. In fact, as you use the cooker, the gunk that buils up will seal those gaps just fine.