I LOVE overnight smokes. That's the only way I do full butts and packer briskets nowadays on my
WSM. I smoke overnight at 225-250F, then crank the temp up in the morning to 275-300F. A 9 lb butt will take longer than a 14 lb brisket, usually 20-25% longer, so that is your answer to the stagger question. At 225F a 9 lb butt usually takes about 19 hours with the process I outlined below. At 250F about 16 hours. Keep in mind that I do not wrap my meat. Wrapping shortens the time again by 20-25%.
Here are a few lessons I've learned so I sleep like a baby, or as well as any 60+ year old baby can sleep.
1. Start with a clean ash bowl. A long smoke can put a lot of ash in the bowl, so empty it before you start.
2. Use a denser charcoal briquette. Use RO Ridge (Embers is the exact same stuff), Weber, or Stubbs. Lighter briquettes like Kingsford will work, but I had greater temp fluctuations using them. I can get rock solid temps for 12-14 hours, or longer, using the denser briquettes.
3. Know your vent settings. I know you're using a temp controller, but I use my vents as the primary air feed with my temp controller as a backup in case the chamber temp drops. By doing so it prevents the temp controller from overstoking the fire. I hook up my temp controller to the
WSM but do not plug it in until later in the smoke.
4. Depending on when I need the meat the next day, I start my fire between 4 and 6 PM if smoking at 225F, 6-8 PM if smoking at 250F. Don't be in a hurry to reach your target temp when you first fire up your
WSM. When I'm setting up a long 225F smoke, I fill my charcoal basket with layers of charcoal and wood chunks until the top of the charcoal pile is about 2-3 inches above the top of the basket. Then I make a little crater in the middle of the pile and add 8-10 hot briquettes. I leave my bottom vents closed, top full open, until the chamber temp appears to stabilize, usually around 190F. Then I crack two bottom vents about 1/16" open. The chamber will stabilize around 225F. Your vent settings might be slightly different because no two WSMs are the same, but they should be close. It can take up to 90 minutes for all the above to happen before it is time to load the meat.
5. Quickly load the meat and put the cover back on. Just the act of taking off the lid will stoke the fire and can add 25F to the chamber temp in no time at all.
6. Once everything has stabilized, I'll plug in my temp controller and set a catch temp, usually about 10F below my target temp. I tend to wake up every 2-4 hours during the night so I don't set any alarms on my Mav. I've done enough overnight smokes that I trust my process. Most times when I wake up the chamber temp is exactly where it was when I last fell asleep, or within 5F. I've done overnight smokes where the outside temp was in the high 20s to low 50s. Didn't seem to make much difference.
7. When I wake up in the morning, I open the side door and use long tongs to knock ash off the coals. That will also stoke your fire. I fully open all the bottom vents and crank my temp controller up to 275-300F. If the chamber temp climbs to 325F or higher, I don't worry about it. Since you are going to be wrapping, the act of taking off the lid will also stoke the fire.
8. Meat temp is usually around 175-185F when I wake up in the morning. After I crank the chamber temp up, it will finish in about 3-4 hours, less time if you are wrapping the meat. When taking the IT of the brisket, use the flat, not the point, even though the point is thicker. The point is full of fat and VERY forgiving. The flat, not so forgiving, so that's what you want to get right.
I strongly suggest an overnight test run before the picnic. Butts are cheap this time of year, so practice an overnight smoke with a 9-10 lb butt. Here's another suggestion: don't use your meat probe to monitor IT on an overnight smoke. Let the meat do its thing while you sleep. Because it is a long smoke, you won't worry when it is stalled for 6 hours, or the meat temp drops, etc. Insert your meat probe in the morning. Heck, I don't even use my meat probes any more. I just use an instant read.
I've said this before on other posts: once you have your process right on an overnight
WSM smoke, the smoke feels like it only took 3-4 hours, not 16-19. The sense of smoking accomplishment is incredible once you master overnight smokes. The WSM makes it easy to get there.
