And the best part? Preparing a perfect rib roast is easy, once you know a couple tricks.
Choosing Your Roast
Shopping for a roast can be confusing because the very same cut of meat goes by several different names. "Prime rib" is the most famous term, but the word "prime" actually describes the grade of the meat, not the cut. (The top three grades of beef are Prime, Choice, and Select.)
Meats graded "Prime" are sold almost exclusively to restaurants, so you probably won't find "prime rib" at the grocery store. Instead, look for roasts labeled "rib roast," "eye of the rib roast" or "standing rib roast." A boneless rib roast may be called "eye of the rib" roast--or if the ribs are still attached, a "standing rib" roast. The meat will be more flavorful if you roast it with the ribs still attached, but a boneless roast is definitely easier to carve. If you buy a roast with the ribs attached, have the butcher remove the the backbone, or the roast will be difficult to carve.
How Much to Buy?
Allow at least six ounces of cooked, trimmed meat per adult. A boneless roast will give you about two servings per pound, and a bone-in roast will give you one to one-and-a-half servings.
Rib roast doesn't need a marinade or any complicated preparations; the meat speaks for itself. If you like, prepare a simple seasoning rub: fresh herbs, lemon zest, garlic, pepper and Dijon mustard are all good matches for beef. To infuse even more flavor into the meat, sliver the garlic, make tiny slits in the roast and insert the garlic bits. You can cover the meat with the spice rub up to 24 hours in advance; wrap it tightly with plastic wrap and refrigerate until you're ready to roast. No need to bring the meat up to room temperature first; you're going for a pink center, so it's okay if the outside heats up faster than the inside. Don't salt the roast until right before cooking.
Place the meat in a roasting pan that's slightly bigger than the roast itself. If the pan is too big, the juices from the meat will spread out in the pan and evaporate. For a boneless roast, it's best to use a roasting rack. If you've chosen a bone-in roast, the bones themselves will serve as your roasting rack. One side of the meat will have more fat on it; you want this side facing up so the meat will baste itself as it cooks. Don't add water to the pan, and don't cover it!
Time and Temperature
There are two ways you can roast: At a low temperature for a long time, or at a high temperature for a shorter time.
Your roast will shrink less if you cook it low and slow, but you won't get the same flavorful, well-browned exterior that a high roasting temperature gives you.
You can also combine the two methods by starting at a high temperature to sear the outside, then turning down the oven after 30 to 45 minutes to finish. If you're roasting at 325 degrees F (165 degrees C), the meat will take about 17 to 20 minutes per pound. If you start the roast at 450 degrees F (235 degrees C) for the first 30 minutes and then reduce the temperature to 325 degrees F (165 degrees C), allow about 13 to 15 minutes per pound.
The Real Secret to a Perfect Prime Rib
A thermometer is the absolute best way to guarantee the roast turns out exactly the way you want it. For an accurate reading, push the thermometer into the middle of the roast, making sure the tip is not touching fat or bone (or the pan!). For medium rare, roast to 130-140 degrees F/55-60 degrees C; for medium, 145-155 degrees F/63-68 degrees C. Remember that the roast's temperature will rise at least 5 degrees after you remove it from the oven. Let the roast stand for 15 or 20 minutes before carving to let the juices return to the center.
The slices taken from the ends of the roast will be the most done, and the middle will be the least done, so you should be able to suit the preferences of everyone at the table. Serve with pan drippings and horseradish on the side.