Originally posted by glenn fleming:
dave:
i have had my WSM for 3 years and i am more confused than ever bout what temp i am actually at.. last wek i smoked a tri tip.. i hung the maverick thru the vent like u said i was a good 30 degrees or more off from the dome therm that i checked in boiling water too be right, so what the heck should i go by?? i did a 14lb brisket on smoke day and went by the dome the whole cook, it was done in 11 hours, but my dome was round 225 all day, but the meat was not great and i think it was done too fast, maybe i should have put it on the rack over the water pan.. just plain confused anymore, and a little frustrated after smokeday.. Glenn in SC
Glenn, your 30* difference in dome temps is not unusual at all...in the first hours of a cook when the meat is still relatively cool. By the end of a cook once the meat is hot, there won't be much difference between the dome gauge and a temp taken at the vent.
No need to be frustrated or confused though, and regarding your brisket cook, it might've just been a less than stellar piece of meat. That's why pros use injections and foil...as insurance against dry briskets...and I've smoked several briskets in my old UDS in less than 10 hours with no foiling, and got great results. I just don't prefer to cook that fast in my 18.5" wsm though.
Back to measuring temp and how the wsm cooks, though...The wsm is not nearly a convection oven, and heat rises and wafts around the meat...the meat being heated by the hot air, and the air being cooled by the meat. SO...just 'cause the wsm is a fairly efficient, vertical, indirect enclosed smoking environment, you know that air does not get hotter all of a sudden after it rises above a grate full of cool meat....UNLESS, it mixes with hotter air, like the heat stream coming up around the outside of the grate. That's why the dome vent temp measurement is better.
Regarding the issue of unevenness and heat circulation though, I'm not saying that rotating or flipping meat is needed...at least not cooking low-n-slow. I leave the fat down toward the fire, and if your pork butts have a thicker side, that's the side that goes to the outside of the cooker where it's hottest if cooking two on a grate. (It's quite often the side with the bone and I turn that side of the smallest bottom grate pork butt towards the door for easier checking.) If only cooking one thing, use the top grate since you'll get more even temp across the grate, but I'd still protect the end of a brisket flat with some fat or foil, especially if cooking in a 18.5" wsm.
Case in point though, regarding your SmokeDay brisket and all this: I was rather perplexed myself a couple of overnight cooks back. On that night, I smoked two big pork butts on the bottom grate (9 lbs+ each), and a decent sized 14lb or so brisket on the top grate. Well, I wanted it done sooner rather than later, but I got all of it done in just 12 hours....water in the pan. I don't remember what I set my Maverick at, and on that cook I had a little space beside the brisket so I put the probe beside it, instead of my usual hanging in the vent. I remember that I wasn't happy with how slow it was in heating, and I had all of the vents wide open.... but I remember that the top vent measurement was somewhere around 240* when I went to bed, and I think it was around 260 or so when I got up. I was cooking a little faster to be done sometime mid-morning, not noon-ish as usual, and although I can't be too sure of just how much faster I cooked than normally, I was happy with how things turned out. From now on though, I'll just go by the vent, and maybe put a (checked) oven therm just inside the door to see how hot the highest grate temp might be.
Well, things to consider on why it went so fast... an overnight cook (no sun on dome), breezy cool temps, and for a windbreak: two drum halves around the cooker which reached not much higher than the bottom of the dome. Next time I'll prop up the windbreak(s) on blocks for better draft mainly, but also to protect the dome from the cool breeze. My point though is that I wasn't really "getting" how hot the heat was coming up under the meat, evidently. I guess the two big butts on the bottom grates were really absorbing a lot of heat since they took up so much of the grate, but a brisket cooked at 250* should take about 1hr/lb. to get tender, and I wouldn't have thought I was cooking over 250*, but maybe I was.
Hope most of that made sense. I didn't get my Sunday nap.
