or should I lower the oven and leave it overnight at 200F? I don't want to risk ruining this big hunk of meat!
Either is likely to be disastrous- are you sure it isn't done? Remember that for a roast this size the temperature at the center will rise quite a bit after removing it from the oven.
Thks for replying. It definitely wasn’t done - internal temp was only 160F. I ended up setting my alarm and leaving it in for two more hours. It came out perfectly! Lesson here is to start earlier for a brisket this size.
I'm glad it worked out for you. I prefer beef very well done myself, but 160 would be considered overdone to the majority (155 is the usual "well done" standard), and in this case the internal temp. would likely rise at least 10 deg. after removing it from the oven.
I am a medium rare person so internal temp would normally be even lower. Brisket is the exception. To get meltingly tender flavourful meat the standard internal temp is 190-210.
Sorry, I misunderstood what you were doing. For the record, I have had success with braises in stopping and restarting- in fact I usually do so with pot roasts because I like to cool the broth to defat it. I think that the difference is that for a complete breakdown of the meat it's not just a matter of reaching a certain internal temperature but of spending some time breaking down the collagens and such.