Some observations

Nature Boy

Last weekend I cooked a 7 pound picnic and a 6 pound brisket side by side and noticed some interesting things. I put them on about 10pm at a steady 250 and went to bed soon after. At 6am, when I woke up, the dome temp was humming along at a steady 240. (gotta love that). Anyway, the brisket was at 155, clearly in the plaeteau. Did not have a probe in the picnic shoulder (but when I did later, it was neck and neck with the brisket).[p]Anyways, I figured since it was for dinner, I would knock the dome temp down to stretch out the plateau, and slow things down a tad. So I tapped the bottom vent nearly closed, and got the temp down to 225 (actually it went down to 205 for a few mintes, then got it stabilized at 225). What was interesting was that the brisket temp dropped 10 degrees to 145, and took several hours to get back to 155. It worked perfectly in the end, as after 19 hours it hit 190 internal, and was done just in time for dinner..and it was probably the best chunk-o-chest I have done.[p]I mainly found it interesting that dropping the temp to 225 caused the meat temp to drop substantially...even though the cooking temp was still much hotter than the meat. I guess the breakdown of connective tissue really does use up a lot of energy. [p]And I learned that slowing things down once you hit the plateau really does a nice job on producing a most-tender brisket.[p]Just some things I thought might be worth mentioning.
Have a great week.
NB

BBQfan1

Nature Boy, Your experience reinforces what I've been noticing in my cooks of late. If I had to give a 'rule of thumb' statement, it would be that 250 dome is the most 'productive' temp for indirect cooking of pork shoulder/butt roasts. By that, I mean that that temperature will produce top quality end results without compromising texture, smoke flavour, fat rendering/connective tissue breakdown etc. Much higher will result in drier product (I'm talking about averaging 250; bumping up to finish will not be a compromise, nor is the temp dipping some overnight etc). This was my conclusion after doing a bunch of butts and picnics at 220-225 in hopes that the lower and slower would result in better product. All it ended up in, was a super long cook with a big push at the end to get the meal to the table!
More related to your post, NB, I too have see a drop in dome from 250 to 225 result in the big internal temp drop, especially if you do it when it's in the plateau range! I had one where I cut it back at top end of plateau 170-175, and had it drop back to low end (150-155) and then I repeated the process all over again at the lower dome of 225, and it took 3-4 hours to 're-plateau'. Didn't make the end result any better or worse, but did allow me to extend the cook out until dinner time! I usually spray/mist with a mix of apple juice or cider, cut with a bit of apple cider vinegar to help retain moisture/create bark on these prolonged cooks.
Qfan