ToddyHill said:
Yesterday, as I was in the early stages of smoking a brisket (which we'll eat later today), I watched a You Tube video from Jeremy Yoder (Mad Scientist BBQ). I was surprised to learn he recommends holding a brisket for 12 hours before cutting it. I've watched several of his videos and have come to recognize he's very knowledgeable on all things brisket.
It's what all of the really popular bbq joints are doing around the state these days. They don't cook those briskets overnight so they can pull them at 9am and serve to you when they open at 11, they cook during the day, finish up in the evening, and hold in warmer ovens overnight until service the next day. Franklin, Truth, Burnt Bean, Evie Maes, and tons more all do this.
They talked about it at camp brisket that I attended last year somewhat and I remember Dr Savell, when asked about the long rest saying something to the effect of "It definitely helps a lot, although we are uncertain of the exact mechanism that's taking place in the brisket. The only reason we haven't studied much in depth yet is we haven't gotten a grant to do so yet, so if any of y'all know a person looking to spend money on a grant for briskets….." The common reasoning you'll hear is that the muscle fibers are constantly contracting as it's being heated/cooked, and the long rest allows them to loosen back out some, which helps with tenderness and moisture retention. They said that's likely part of it, but they wanted to study it more.
All that to say, yes, while a short 2-4 brisket rest is almost necessary, you do benefit from a long hold of 8+ hours. You can hold up to 18-24 hours before the quality starts to degrade.