So I am doing a prime rib for only the 2nd time ever. I have read the various threads on here about prime rib, and on various other websites. I have decided this time to go the reverse sear method and cook at low heat (last time I did the sear/low heat method). The thing is, we are going to be having Christmas lunch and I need to have the prime rib ready for around 12pm. Or, I should say, I need to take it off the grill by around noon-ish for a 10 minute trip to the host's house. So, it can rest in a cooler wrapped in foil/towels for a while after I remove from the grill before we need to eat. (eating around 1ish).
I have read people say to take it out of the fridge an hour before you put it on the grill/in the oven. I have also read that at 225 degrees the roast should take from 20 to 30 minutes per pound. The roast is 6.2 kg which is over 13.5 lbs. What I am confused about with regards to that is if the length of the roast is really going to effect the cooking time that much. It is 16" long so the weight isn't from the thickness of the roast but the length.
I am trying to figure out what time I need to start cooking in order to be sure I am ready by noon. I will be using a wireless thermometer to monitor both the grill temp and the meat temp. This site has a bunch of timing info based on user feedback: http://playingwithfireandsmoke.blogsp... . Based on that I figure it would be 5 hours max but I don't know if people took out the roast from the fridge and let the temp rise to room temp before cooking it or not. I read if you don't do that it can add 20% to the time it takes to cook.
So, some other factors. I will be using a ceramic style BBQ (i.e. Big Green Egg style but different brand) I have had good luck with keeping stable temps when doing stuff on it before. The roast has the bone cut off but tied back on. I was planning on cooking it with the bone tied on.
If I find that with an hour to go it isn't as far along as I wanted, what would raising the temp by 50 degrees for the rest of the cook do to the meat? I imagine it would taste no worse than if I had cooked it at a higher temp the whole time.
Anyway, this is a long post already.... On any other day it probably wouldn't be a big deal to wake up early but I am worried it will be a LONG day already. If I need to leave the roast out for an hour before cooking, cook for 4.5 to 5 hours, it means that I am starting around 6am or earlier. Am I being overly cautious to start that early and will it likely cook a lot faster because the weight isn't from thickness but length?