Well, I tried this for the first time last night and it was a disaster of epic proportions. I still don't know what happened so if anyone has an idea, let me know.
I bought a rib roast from Sam's Club that was almost 13 lbs as I was feeding 10 adults and wanted some leftovers. Unfortunately, they take their bones out, but with the price of that meat being $84, it was too good to pass up.
We were planning on eating around 7:30 and unfortunately, a few guests couldn't get over any earlier so this time was non-negotiable. Figuring about 20 minutes per pound of cook time, 3pm was a good start time, finish close to 7pm and give it 20-30 minutes to rest. Rubbed with some roasted garlic, kosher salt, pepper, and rosemary on the outside. Put on my roasting pan and stuck it in the oven.
Now, as I've never cooked anything like this before, I didn't have a meat thermometer so I went out and bought
this one to make this. I put the thermometer in right in the deepest part of the meat. Started the oven at 500 degrees for 5 minutes and then turned it down to 300.
Initially, the thermometer was reading 275 for the oven temperature but about 30 minutes later, it dropped to only reading ~250. This wasn't good. Luckily, my mother who was over lives close by and has a meat thermometer although it's not one that can go in the oven. I figured I'd have her bring it over and do a check to compare and see where I was. After about 2 and a half hours of cooking, she left to go get it and came back about 20 minutes later. I take the meat out, stick in her thermometer and............
140 degrees!! Huh?
Somehow, that 13 lb piece of meat went way over and 3/4th of the time. At this point, I didn't put it back in, wrapped it in some foil, and just hoped for the best. It was to no avail. Not only was the temp way to high already, but now the meat is out more than an hour and a half from eating time. So it got to sit there for an hour and a half and continue to cook inside while sitting there. By the time I cut into it, there wasn't a shred of pink in it.
Needless to say, it was terrible. I truly have no idea how it cooked so fast and so much but I don't think I'd be willing to try again. Ugh.