Ok. I am cooking 4 pork shoulders, average weight is about 7.4 lbs. I am using a Brinkmann electric smoker. How long should I cook them for? I have done a 9lb before and I cooked for 8 hrs on the smoker and finished it in the oven at about 125 for 10 hrs and it came out awesome. Should do the same for this time?
I'd expect them to go a little longer than 10 hours, just because there is more density (the meat) in the smoker. But i'd start checking at 10 hours.
Cook them until their internal temperature reaches about 195-F to 200-F. However long that takes. If less than about 190-F internal they will be tough.
I have that same Brikmann rig. It is designed to cook at a steady 250F . If doing one or two, I always plan 18 hours and for 3 or four butts 24 hours.
That mass of cold meat will take some time to get up to cooking temp in that smoker, preheated or not.
Also, adding the wood every hour or 2 also causes temp drop so you add cooking time there.
If me, I;d cook the butts on the smoker for 8 to 10 hours and then move to the oven for finishing. For me I keep the same 250F temp for the oven and put the butts in a rack in a pan and tent with foil to keep moisture loss down (since the oven does not have a water bowl like the smoker. but I've alsways had crispy bark when tenting or wrapping). Just cut a slit for you remote probe termometer thru the foil.
Bumping oven temp from 125F to 250F has never caused me problems at all but you can drop it to 225F if worried. Also going higher than 125F will shorten cook time.
They are done when they are done, and I do the 195F -200F internal temp and then rest for a while (it's almost too hot to pull at the temp anyway) and then hold in oven or wrap and place in cooler and use a heating blanket or warm bricks to keep warm till serving.
Those Brinkmanns are awesome but lots of variables make it hard to have your butt done at an exact time if serving for company or a party.
You can plan for longer as jeanmarieok suggested. Maybe as long as jjjrfoodie suggested -- I'd go with the higher temps, too. They will probably be done at different times. As soon as one is done, remove it, wrap it in foil, wrap that in a towel and stick it in a cooler (a process referred to by some smokers as FTC). It will continue to cook, of course. You can hold them a few hours this way. I have found no difficulty holding pork butt 3 hours this way and some folks report that with a good cooler, five hours is fine.
Your oven will keep 125F? Not many household ovens go much lower than 200F. You won't get pullable pork (not sure if that is your goal or not) no matter how long you hold it at 125F.