My son was home for 10 days after graduating from Arizona State and asked me to make a brisket. He went to the butcher shop and picked up a prime 12# flat. My first brisket was an 8.5# prime flat from the same shop. The first brisket took 14 hours and probably could have gone and hour or two longer. We were planning a small party for 5 PM on Saturday and I wanted to allow plenty of time so I started the brisket at 7:30 of Friday night. I smoked at 180 until 10:30 at which time I bumped it to 225. At 3:30 AM I pulled the brisket (150 and 155 on the probes) and wrapped in butcher paper. Inserted the two probes again and raised the temp to 275 and proceeded back to bed for a little more sleep. When I checked the brisket at 7:00 it was 180 and 185 on the probes. Not wanting the brisket to be done at 10 AM I backed the temperature off to 250. It slowed down but at noon it was ready to come off. Thermapen showed temperature at 200 to 205. My friend gave me a pair of Swaddler Pillows. I pulled the brisket from the paper and wrapped in foil and stuck it in a cooler with the pillows. When I pulled the brisket at 5:15 it was still good and hot. Great bark and smoke ring but it was like a medium well steak with almost no moisture. Flavor was great and it was definitely tender but it just wasn't very moist. I never suspected a 12# piece of meat would cook in less than time my smaller first brisket. I assume the long rest in the cooler is the culprit for the dry brisket. Prime beef isn't cheap so Its somewhat disappointing that the results weren't better.