How To Cook Prime Rib, According to America's Most Famous Butcher Pat LaFrieda

When you think of the perfect holiday meal, you probably picture a beautiful roast at the center of the table. And no roast really says “special occasion” quite like prime rib.

But how do you make it come out with a perfectly caramelized crust, juicy and cooked just right inside like the drool-worthy pictures on Instagram and Pinterest? With the help of third-generation butcher and author of Meat: Everything You Need to Know, Pat LaFrieda!

We got him to share his expert advice and secrets so you can confidently cook prime rib like a pro. Here’s everything you need to know.

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How To Cook Prime Rib

While cooking time guidelines are helpful when it comes to planning, as we all know—prime rib is not a cheap cut of meat—so the last thing you want to do is overcook it. That’s why LaFrieda says “the single most important thing for cooking prime rib is a thermometer.” Along with the detailed advice below, this very simple, inexpensive kitchen tool will help ensure your prime rib comes out perfectly every time.

With that in mind, assuming you’re starting with a prime rib roast that has an internal temperature of 38° (just out of the refrigerator), LaFrieda says the basic formula for perfect medium-rare prime rib is 13 to 18 minutes of cook time per pound at 325°. See below for a wider range of wellness and oven times.

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Here are the thermometer temperature readings (when inserted into the center of your prime rib) that you’ll want to look for, depending on what doneness you prefer: rare, medium, well-done or somewhere in between.

• Rare: 120-130°

• Medium-Rare: 130-135°

• Medium: 135-145°

• Medium-Well: 145-155°

• Well-Done: 155-165°

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What Size Prime Rib Should You Buy?

When shopping for prime rib, the general guideline is about one pound per person, but the number of side dishes should also be considered. If you’re planning a large holiday meal with lots of sides, you can get away with a half pound per person.

And quality matters, too! “Always look for the most marbled meat for prime rib—prime or choice grades,” advises LaFreida. LaFrieda sells meat on his website, so it's possible to buy prime rib from the man himself. If you're going for a local-to-you option, he recommends asking your butcher to remove the chine bone and feather bones from the rib roast so you will be able to slice straight through the meat, between the bones, once the roast is done.

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Optimal Cooking Times for Different Prime Rib Weights Cooked at 325°

Here are at-a-glance optimal cooking times for roasting at 325°, depending on the size of your roast. Again, this is assuming you are starting with a prime rib roast that has an internal temperature of 38°, which is the average temperature of a refrigerator. If your prime rib is colder than this, you may need to cook it longer. And if it’s warmer than this (say, room temp), it will cook much more quickly, so you should reduce the total cooking time. Again, this is why pairing guidelines with a thermometer is the key to prime rib success.

• 4 pounds: 1 hour

• 5 pounds: 1 hour and 15 minutes

• 6 pounds: 1 ½ hours

• 7 pounds: 1 hour and 45 minutes

• 8 pounds: 2 hours

• 9 pounds: 2 hours and 15 minutes

• 10 pounds: 2 ½ hours

• 11 pounds: 2 hours and 45 minutes

• 12 pounds: 3 hours

• 13 pounds: 3 hours and 15 minutes

• 14 pounds: 3 ½ hours

• 15 pounds: 3 hours and 45 minutes

• 16 pounds: 4 hours

• 17 pounds: 4 hours and 15 minutes

• 18 pounds: 4 ½ hours

• 19 pounds: 4 hours and 45 minutes

• 20 pounds: 5 hours

Oven Temperature Guidelines for Your Desired Prime Rib Doneness

If you prefer to roast your prime rib a bit “lower and slower” (at 300°) or want to roast it a bit more quickly (at 350°), here are additional formulas from LaFreida to help you estimate total cooking time, based on the size of your prime rib roast. LaFreida’s favorite cooking temperature for cooking prime rib is 325°, which he thinks creates the perfect medium sear. We’ve included cooking details for that temperature below as well.

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How Long To Cook Prime Rib at 300°

Rare: 10 to 15 minutes per pound
Perfect medium-rare: 15 to 20 minutes per pound
Medium: 20 to 25 minutes per pound
Medium-well: 25 to 30 minutes per pound
Well-done: 30 to 35 minutes per pound

How Long To Cook Prime Rib at 325°

Rare: 8 to 13 minutes per pound
Perfect medium-rare: 13 to 18 minutes per pound
Medium: 18 to 23 minutes per pound
Medium-well: 23 to 28 minutes per pound
Well-done: 28 to 33 minutes per pound

How Long To Cook Prime Rib at 350°

Rare: 6 to 11 minutes per pound
Perfect medium-rare: 11 to 16 minutes per pound
Medium: 16 to 21 minutes per pound
Medium-well: 21 to 26 minutes per pound
Well-done: 26 to 31 minutes per pound

How To Reverse Sear Prime Rib

Reverse searing is a great way to ensure that you have an evenly cooked roast with a great crust and no band of overcooked meat between the two, says LaFreida. “It’s actually my preferred method of cooking prime rib,” he adds.

Here's how to do it: Follow the oven temperature/cook time guidelines above but take the roast out of the oven 10 degrees below your desired temperature. So, as a reminder, here’s what you’ll be looking for on your thermometer inserted into the prime rib.

Rare: 115°
Medium-Rare: 125°
Medium: 135°
Well-Done: 155°

Once you’ve removed the roast from the oven, crank the heat up to 550°. When the oven reaches 550°, put the prime rib back in for 7-10 minutes, until the outside has developed a mahogany-colored crust. The prime rib will have risen in temperature by 10°, bringing you to the desired internal temperature but with a spectacular crust on the outside. It's truly the best of both worlds!

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