Mixed Messaging on Cook Times for a BIG Prime Rib

Papalikes

I have a 19 pound bone-in prime rib roast in the fridge for Santa's big day and have been researching cooking times for the "low and slow" method.  

At 250 degrees, some posts say 25 mins. per pound (as an estimate) and others says that the size of the roast doesn't really matter as long as it is the same thickness.  Put another way, at 4 inches thick, the roast should cook for about the same time if is 8 inches long, 10 inches, or 18 inches.

I have a lot riding on this roast and wanted to get some feed back from my fellow Eggheads.  I know which direction I am leaning, but was hoping for a quick sanity check.

Thanks Brothers (and Sisters?) and have safe and Happy Holidays!

SMITTYtheSMOKER

Guess it is a little too late to suggest a practice cook for an important meal?

One thing that you should keep in mind is that you can always increase the cooker temps to move the cook along if you don't see it mvoing fast enough.

 

Good luck and Happy Holidays.  

henapple

You had me at 19lbs...holy crap.

Dave in Florida

Good information. 

http://playingwithfireandsmoke.blogspot.com/1996/03/beef-standing-rib-roast-prime-rib.html

Skiddymarker

The per pound rule doesn't work with roasts that get longer but bot thicker. Turkeys and chickens get rounder as they get bigger so a per pound rule works. 

Check this link:

http://amazingribs.com/recipes/beef/prime_rib_roast.html

Assuming it fits, your 19# monster will cook in the same time as a 6#. Check some of the other threads here as well. 

Cook time will be about 3-4 hours max. 

tays44

Too late now as Christmas is over, but when I am cooking things like this, I throw cook time out the window.  Depending on how much time I have, I try to go as low as possible.  With that 19 lb bad boy, I'd likely do about 300* and just cook until I hit my desired temp, regardless of the time it takes.  This wya ensures that you take your time and do it right.  Once I hit 135 I pull.  However I leave a thermo in at all times.  So after a while, you can see how quick your meat is heating up.  If you are going up 15 degrees every hour, do the math on when you need to start your sides or other items. 

CeramicChef

I don't think I've used any kind of per pound rule since I began using ceramic cookers about 20 years ago. You'd be surprised how bad bimetallic thermometers are across a wide temperature range at indicating a correct temperature. We could go on and on here, but I would send you to the following URL at Amazing Ribs for why your typical dome thermometer is useless. http://amazingribs.com/BBQ_buyers_guide/thermometer_buying_guide.html Once you understand that cooking to a specific internal temperature is the only way to cook, all your concerns about per pound goes right out the window. Sure, there are per pound guidelines, but those are generally with respect to time. Simplify your life and invest in a good instant read thermometer and a good two-lead thermometer so that you can get accurate grill level temps and internal temps.