I just did my 3rd major smoke last night . Here's the details of that smoke.
Charcoal Ring: Full to rim with Kingsford Comp.
Small Can in center for reception of hot charcoal. Can was filled to top. Tall tomatoe juice can, by the way.
WSM brought up to 200*, all vents wide open. Upon reaching 200*, shut down bottom two vents, closed down third to about 1/4 open. Top vent wide open.
Temp coasted up to 232-235 (doing rotisserie chicken in the WSM, yes, that's with a rotisserie on top of the middle chamber of the WSM). Temp held rock steady in the 232-235 range for 2 and a half hours. Then it started climbing. Nothing else had been changed, tinkered with or peeked at. The temp rose to about 250-260 and held there.
This has happened before, at about the same time point into the smoke.
I closed down the vent further, to the point that there's barely a crack to be seen. I've plugged the additional eyelets not being used for this smoke. I even closed down the top vent to about half, to no effect.
I'm glad I put wheels on the WSM, because the wind direction changes so much here in the Denver Metro area that I'm moving the WSM around to keep the opened bottom vent away from the blowing wind.
During this time frame, I've had to resort to the burping trick to get the temp to drop, but that's just a temporary thing, due to the excellent recovery rate the WSM possesses.
The small wood chunks weren't burning, just smoldering as I'd expect them to.
I thought adding cold water to the water pan might help, but no, not even that had an effect.
I've looked through the references on this as well as off site links and don't see anything that addresses this problem.
I have a theory that as the charcoal ignition from the center, reaching outwards is igniting more charcoal by count then when it started out, that is to say, starting out, let's say the minion method of starting ignites an additional 20 briquettes, but as it progresses outward, more briquettes are being ignited. Imagine each progress as a ring of briquettes, the ring gets greater in diameter, consequently the circumference gets wide, containing more briquettes.
I question the validity of that theory because later on (3+45 or so), the temp drops back down to the 230 range.
NOTE: To clarify the 3+45 mention, for those never having been exposed to this form of time reference, it means 3 hours and 45 minutes from start time or Zero hour. It's commonly used in the military for whatever project is time-based with subsequent steps being related to Zero hour.
I know that the above statement is going around the block a couple of times but, hopefully you see what I'm trying to say.
I'm really impressed with the performance of the WSM and it's recovery rate (REALLY glad I made the jump to charcoal), but what am I missing at the 2+30 point that is kicking the temps up.
I've got the big family smoke-off coming up Saturday and I know that I'm giving the other smokers a big advantage because I'm learning a new smoker and the techniques involved. I'm not to the set and forget stage yet.
By the way, I'll be smoking 17 lbs of Beef Short Ribs.........At $6.69 a lb, I don't want to blow this one.
And, btw, the chicken came out great. Took 6+ hours. I think the altitude has something to do with that.
Thanks for any and all help.