Expert: Steve Hanagan - 12/25/2007

Question
Hi, Steve.  Approximately how many minutes per pound should I roast a bone-in 20 lb. prime rib roast?  If you have an idea of minutes per pound in a convection oven, that would be great.  Thanks for any help you can give me.
Margie

Answer
With such a large roast, I would say you should expect 12 minutes per pound for medium-rare, or roughly 4 hours in a standard oven.  With the convection oven, I'd say closer to 2.75 to 3 hours.

Don't forget to account for carry-over cooking.  With such a large roast you can expect at least another 10 degrees increased temperature while the roast is resting.  Don't rest it more than 20 to 30 minutes or it will continue cooking to well done in no time.

NOTE:  If your oven is a multi-rack convection, turn that feature off and use only the regular convection.

Hope this helps.