Cooking a perfect prime rib roast that is juicy, tender and flavorful with a crisp, browned crust is the goal, but it’s important to let the roast rest after cooking before slicing and serving. The resting period allows the juices to redistribute through the meat, resulting in a more evenly cooked, moist and tender roast. However, you don’t want the roast to cool down too much during this rest time. Keeping the roast warm while it rests is key for serving your prime rib at its best.
Why is resting important?
Resting the roast after cooking serves a few purposes:
- It allows the juices that were driven to the center of the meat during cooking to redistribute back out towards the edges. This results in a more evenly moist and tender roast.
- It gives the proteins time to relax after cooking which helps make the meat more tender.
- It prevents losing too many juices when you slice into the roast.
For these reasons, it’s important not to skip the resting period. A general rule of thumb is to let the roast rest for at least 15 minutes before slicing and serve warm, not hot.
How long should you let prime rib rest?
For a prime rib roast:
- Let rest 15-20 minutes for a 3 to 4 pound roast.
- Let rest 25-30 minutes for a 6 to 8 pound roast.
- Let rest 30-40 minutes for a 10+ pound roast.
You want the meat to retain enough heat while resting so that it is still warm when sliced and served. The larger the roast, the longer the resting time should be. The roast will continue to cook a bit more from residual heat during the resting period as well.
How to keep prime rib warm while resting
Here are some tips for keeping your prime rib roast warm while it rests:
Tent foil loosely over the roast
After removing the roast from the oven, tent it loosely with aluminum foil. You want the foil to just drape over the top, not wrap tightly which would trap steam. This helps retain some heat and lets some steam escape.
Wrap in towels
For added insulation, you can wrap kitchen towels around the foil-tented roast. Use clean towels and wrap them loosely around the pan the roast is in.
Keep on a heated platter or pan
Placing the roast on a heated platter or pan will help retain heat. You can heat the empty platter/pan in the oven at the lowest temp while the roast rests nearby.
Keep near the oven vent
Position the roast near the vent of your still warm oven so residual heat helps keep it warm.
Use a warmer device
You can place a tray or electric warmer device, turned to low, under the roast pan/platter to provide gentle heat from the bottom.
What not to do
Avoid these common mistakes when resting prime rib:
- Don’t tightly wrap in foil which traps steam and overcooks the roast.
- Don’t let it sit right in the turned off oven which retains too much heat.
- Don’t transfer to an unheated platter or pan.
- Don’t cover tightly with an unheated lid or dome which drops the temperature quickly.
Use a meat thermometer
Using an instant read thermometer is vital for cooking prime rib to perfect doneness. Insert the thermometer into the thickest part of the roast, without touching the bone.
Target temperatures for various doneness levels:
| Rare: | 120-125°F |
| Medium rare: | 130-135°F |
| Medium: | 140-145°F |
| Medium well: | 150-155°F |
| Well done: | 160°F+ |
The temperature will rise about 5-10°F during resting. Remove it from the oven when it’s 5-10° below your target temp.
Rest on a cutting board
For easier slicing, transfer the roast to a cutting board after the resting time. Use a large carving or wooden board. Have it ready near the roast so you can quickly move it and start slicing and serving this delicious roast while it’s still warm.
Carve across the grain
Always slice prime rib across the grain of the meat, not parallel with the bones. This gives you nicely tender slices that cut through the muscle fibers. Cut on a slight diagonal for wide, even slices.
Serve with au jus and horseradish
For serving, be sure to pass the defatted au jus sauce as well as horseradish sauce. The flavorful au jus from the resting juices gives great flavor over the resting roast. The horseradish sauce pairs perfectly with prime rib adding a little zing.
Start checking temperature early
It’s better to start checking the temperature with your meat thermometer a bit early rather than risk overcooking. Prime rib roast cooked beyond medium rare can quickly become dry. Monitor it closely towards the end of estimated cooking time.
Use a probe thermometer
For the most convenient monitoring, use a digital probe thermometer that stays in the roast during cooking. This way you can monitor the temp precisely without repeatedly opening the oven.
Cook at low temp
Cooking the roast at a low temperature (250°F-325°F) results in the most evenly cooked, tender prime rib. The lower oven temp gives a nice rosy pink center without overcooking the outer layers.
Dry brine for flavor
Dry brining the roast uncovered in the fridge a day ahead helps season it all over and enhances juiciness. Simply rub with salt and let rest on a rack.
Allow ample resting time
Be sure to allow at least 15 minutes of resting time, more for a large roast. Resist slicing in too soon or you’ll lose those flavorful juices as they run out.
Use a leave-in thermometer
A digital thermometer with a probe that stays in the meat lets you routinely check temp without losing heat by opening the oven. This helps prevent overcooking.
Baste during cooking
Brushing the roast with melted butter or herbs infused olive oil during cooking helps keep the outer surface moist and tender.
Blot before serving
After slicing the prime rib, blot each slice with a paper towel before transferring to plates or a platter for serving. This absorbs excess juices.
Sharpen your knife
Using a nice sharp carving knife makes slicing the roast easier and gives you clean, thin slices. A dull knife can crush and tear the meat fibers.
Remove bones first
For easy carving, remove the rib bones before slicing by cutting along the bone. You can then neatly slice perfect portions without navigating around bones.
Conclusion
Following these tips will help you achieve prime rib perfection. Allowing the roast ample resting time is key but keeping it warm while it rests ensures ideal serving temperature. Using a meat thermometer takes the guesswork out of doneness. Slice across the grain for tender slices. Serve your perfectly cooked, juicy prime rib with rich au jus and horseradish sauce for a celebratory meal.
