The best way to cook prime rib (traditional vs. prime rib 500 rule)

Prime Rib makes for an incredibly succulent and flavoursome beef roast, but it’s an expensive cut that you want to be absolutely perfect. So what’s the best way to cook it? A traditional oven roast, or the popular “foolproof” prime rib 500 rule?

To help you decide which approach is best for you, I reviewed twenty different recipes for prime rib roast. I’ve figured out the pros and cons of the different methods to help you choose an approach, or a recipe, that suits you the best.

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How to cook a prime rib roast

All the recipes I reviewed are for an oven-roasted prime rib. A few readers ask about using an instant pot, but the response is usually the same – rib of beef is best done in the oven.

And there are two different approaches you can take:

  • a traditional oven-roasted method
  • the newer prime rib 500 rule, or foolproof prime rib

So which is the best way to cook your prime rib? Let’s see how they compare.

Traditional oven roasted prime rib

Most of the recipes I reviewed take the traditional approach – start your beef in a hot or very hot oven, then lower the temperature after a short time.

The goal of this approach is to quickly sear the outside to develop flavour and a nice crust, then do the bulk of the cooking more slowly at a lower temperature. I found this approach very popular in my review of roasting a turkey as well.

Even though this is a traditional approach, there is a lot of variation in how the different authors approach it.

The starting temperature varied from 400°F to 500°F (200°C to 260°C), and the temperature for the slower cooking phase from 250°F to 375°F (130°C to 190°C).

The most popular approach though was to start at 450°F (230°C) and finish at 325°F (165°C).

How long in the oven?

The time at the first temperature was fairly consistent, with most recipes recommending 15 to 20 minutes. A few were a little longer, but none more than thirty minutes. And those using the hottest temperatures tended towards fifteen minutes.

The time at the second temperature is best described as “until your beef is done to your liking”. And the most accurate way to judge this is by measuring it’s internal temperature, which we’ll cover shortly.

This is obviously not very helpful from a planning perspective though, so many authors offer some guidance on approximate cooking times to give you a rough idea. If you work with 13 to 15 minutes per pound you’ll be close, and if you prefer it rarer rather than more medium, then your best bet is to work with the lower end of this range.

How to oven-roast prime rib (traditional approach)

  1. Start your prime rib at 450°F (230°C) for 15-20 minutes.
  2. Then lower the temperature to 325°F for 13-15 minutes per pound (165°C for 29 to 33 minutes per kg).

The prime rib 500 rule (foolproof prime rib)

The newer method recommended by the other authors is a little more unusual.

It goes by a variety of different names, including:

  • foolproof prime rib
  • no peek method
  • prime rib 500 rule
  • 500 degree method
  • closed oven method
  • oven off method

Whichever name you’ve heard used, the approach has the same goal as the traditional method – start your roast hot to get a nice crust, then cook the meat slowly at a lower temperature. The difference here is that the second stage is actually done with the oven turned off.

What?!?

Yep, after cooking your beef for a short period at a very high temperature, you turn your oven off and leave the door closed, allowing the residual heat to slowly cook the meat through.

How the prime rib 500 rule works

All the recipes I reviewed are very consistent in their approach:

  1. Cook your prime rib at 500°F (260°C) for 5 to 6 minutes per pound (11-13 min/kg). This is why it’s called the 500 rule.
  2. Turn your oven off and leave the meat in the oven, with the door closed, for exactly two hours.

In all five recipes the second stage is two hours. This can work for any size piece of meat because the first stage varies based on its weight. This way a bigger cut will have longer at the higher temperature.

It’s also why the method is sometimes referred to as a foolproof prime rib. Once you turn the oven off you know exactly when your beef will be ready.

One thing all five authors very strongly advise is that your oven door must stay closed for the entire two hours. Some of them have photos of strongly-worded signs on their oven doors commanding nosey family members to keep out!

This is important because your oven will lose significant heat if you open the door, and without being turned on it can’t recover the lost heat.

Unfortunately, based on the experiences of some of these recipes’ readers, your oven may lose significant heat even without opening the door .

Caution sign.

Beware of fast-cooling ovens

More than a few readers reported issues with this method, ranging from their prime rib being significantly undercooked to “raw”. One reader even found that her beef was cold and the fat was congealing! I’m guessing these people would object to the name foolproof prime rib.

During the two hour “off” period, the temperature in the oven will vary based on how well your oven retains heat. I know my old oven used to lose all of it’s heat in about an hour, whereas my new one can hold significant heat for several hours.

A couple of readers who found that the 500 rule left their meat undercooked had gas ovens, so there may be something different about how gas ovens retain heat. And Darcey from Foodies and Wine thinks it may be because of the cooling fan in modern ovens.

Because of this uncertainty, it’s worth using an oven-safe meat thermometer if you use this approach, at least the first couple of times. That way you can keep an eye on the internal temperature of your roast without opening the oven.

If it turns out that your beef is undercooked after the two hour period, most of the authors recommend turning your oven back on to 375°F (190°C) and cooking your prime rib a little longer.

Be aware though that a couple of readers commented it took up to an additional hour to reach the right internal temperature. No great if your guests are hungry and your sides are going cold!

Using the prime rib 500 rule

I’ve never tried this method of roasting meat, so I can’t comment from personal experience. Based on what I’ve read from these recipes and their comments, this method carries some risk that your beef will be undercooked at the end of the two-hour period, which is exacerbated by the fact you can’t open the door to check the internal temperature of your meat.

That said, the authors, and many of their readers, have great success with the no peek approach, so if you’re confident your oven retains heat well, it’s certainly a very easy method to roast your prime rib.

How to cook to the prime rib 500 rule

If you do want to give it a go, it’s a simple process:

  1. Start your prime rib at 500°F for 5 to 6 minutes per pound (260°C for 11-13 min/kg).
  2. Then turn your oven off and leave the meat in the oven, with the door closed, for exactly two hours.
A two-rib prime rob roast, golden brown on the outside and bright pink in the middle, with the text how to cook a prime rib, traditional vs prime rib 500 rule.

Traditional oven roast vs. prime rib 500 rule

The two different approaches have advantages and disadvantages depending on what matters to you the most. But for me, based on everything I’ve read in researching this review, the answer is fairly clear.

The traditional approach to cooking a prime rib is more reliable

The traditional approach is the truly foolproof method, because you just keep cooking your prime rib until it reaches the desired internal temperature.

And because the oven is turned on, the suggested time of 13 to 15 minutes per pound for the second stage is likely to be fairly reliable.

That said, the newer approach definitely has appeal.

The prime rib 500 rule is easier, but it is risky

The attraction of the no peek approach is the fact that once you’ve turned the oven off you know you have exactly two hours to go.

This sounds great in theory, but there’s risk if your oven cools too quickly. As we’ve seen, more than a few readers of these recipes found their meat was significantly undercooked after the two hour oven off period. Check out the reviews on this Serious Eats closed door prime rib recipe for a lot of examples.

This problem occurs because either by design or due to age some ovens don’t retain heat as well as others. So if you’re going to give it a go, it’s probably worth buying an inexpensive oven thermometer and doing a dry run to check your oven. Heat it thoroughly to 500°F (260°C) with the oven thermometer inside, then turn it off and keep an eye on the temperature over the next two hours. If it drops quickly you’re probably going to have a problem.

It’s also worth using an oven-safe meat thermometer if you use this approach (and honestly, with the traditional approach as well). That way you can make sure your meat is steadily increasing in temperature without opening the oven.

It’s also worth noting that some authors recommend the 500 rule only be used for mid-sized prime ribs. This is because smaller cuts may be overcooked after two hours and larger cuts may burn with the longer time at 500°F. Overall the guidance seems to be to only use this method for prime ribs between four and ten pounds.

One last thing worth considering. With the prime rib 500 rule, you can’t use your oven for anything else.

What’s the best approach to cooking a prime rib?

A prime rib roast is an expensive cut of meat that you’re probably serving to a large group of guests for a special occasion, so you really want it to be perfect.

Based on what I’ve seen, I believe your best bet is to go with the tried and tested traditional approach. The 500 rule method works wonderfully for many people, but it fails quite a lot of people as well. Not exactly the foolproof method it claims to be!

So if you’re looking to make your Easter, Thanksgiving or Christmas table centrepiece a prime rib roast this year, the traditional approach will lead you to success, and it looks something like this:

  • Start your prime rib in a hot oven of 450-500°F (230-260°C) for 15 to 20 minutes.
  • Then lower the temperature to 325°F (165°C) and cook it until the internal temperature is 120°F (49°C).
  • Rest it for 15 to 20 minutes for a perfect medium-rare finish (130°F/54°C).

And if you’re looking for some great sides to have with it, I’ve got a few reviews that might help:

An apron on a wooden surface with three wine bottles and the text cooking lubricant required.
Check out this fun apron, the perfect gift for those who love to cook with a glass of wine in their hand!

Prime Rib Frequently Asked Questions

What’s the best oven temperature for roasting prime rib?

The most reliable approach is to start your prime rib at 450°F (230°C) and finish it at 325°F (165°C).

How long does prime rib take to roast?

Start your prime rib at a high temperature for 15-20 minutes, then lower the temperature and roast it for 13-15 minutes per pound (29-33 min/kg).

What is the prime rib 500 rule?

Another approach to cooking prime rib which involves cooking it for a short time at 500°F (260°C) then turning the oven off for 2 hours.

Does the prime rib 500 rule work?

It works very well in ovens that retain heat well. If your oven loses heat or cools quickly when turned off, the 500 degree approach may undercook your prime rib.

What’s the best way to cook prime rib?

The most reliable approach is a traditional oven roast, starting at a high temperature and finishing at a lower temperature.

How long should prime rib rest after cooking?

Allow 15 to 20 minutes for the juices to redistribute evenly and the temperature to stabilise.

What internal temperature is prime rob done at?

The most popular way to eat prime rib is medium rare, which is 130°F (54°C).

Recipes included in this review

The recipes I used for this review are listed below. You can also find them all on my prime rib Pinterest board.

Traditional oven roast prime rib recipes

Prime Rib 500 Rule recipes

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