How Long to Defrost Prime Rib: Safe Tips and Methods

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how long to defrost prime rib

Prime rib is a larger cut of meat that takes time to prepare for cooking. A well-laid-out plan from the beginning will make the feast a definite crowd-pleaser. Here we’ll go over how long to defrost prime rib so you know exactly when that flavorful beef should hit the grill. 

How Long To Defrost Prime Rib?

A frozen prime rib roast will take 4 to 7 hours per pound to thaw. The average prime rib roast of 5 pounds should be completely thawed in 24 to 48 hours. It’s best to leave your prime rib in the fridge to defrost the whole way, but you can speed up the process by submerging it in a sink full of water while still in its packaging. 

What is Prime Rib?

Prime rib gets its name due to the fact that it’s a primal cut or one on the outside section of the beef that a butcher would cut first. This cut is from the lower ribs toward the loin. 

Some butchers will cut out the ribs from this section. Once the ribs are removed from the meat portion, this is called a standing rib roast. It’s the same meat minus the bone. The rib bones could be cut off and tied back onto the rest of the roast with twine. 

how long to defrost prime rib

You can also remove the bone yourself prior to cooking. Cooking the roast bone-in will add flavor and protect the meat from searing flames. Removing the ribs before cooking makes for an easier carving once your roast is ready to serve. 

Different Methods of Defrosting

There are various ways to defrost prime rib. The typical prime rib roast will weigh from 3 to 6 pounds. However, you can find them larger if desired. To estimate the size of rib roast you’ll need,  figure on 1 pound per person you’re feeding. 

Refrigerator Method

Our preferred method is to thaw a roast in the refrigerator. Your refrigerator is a controlled environment, which makes it the safest place to store raw meat. However, thawing a large roast in the refrigerator is also the most time-consuming method. 

After removing your prime rib from the freezer, place it in a large roasting pan. With this method, you can leave the rib roast wrapped or, if you prefer, remove the packaging and pat dry with paper towels. 

Line the roasting pan with paper towels if you decide to leave the roast uncovered. Once you’re done drying and setting the meat in a roasting pan, place your prime rib roast on the bottom shelf of the refrigerator until it’s closer to cooking time. 

Ice Chest Method

Thawing a prime rib roast in a cooler is easy and convenient if you are camping, picnicking, or tailgating. Defrosting your prime rib in a cooler is also a great idea if your refrigerator is on the smaller side or maybe it’s already full of other food for the approaching feast. 

The ice chest method, however, requires a bit more attention. For example, you will have to check on the cooler from time to time to make sure all the ice hasn’t completely melted. 

As a rule of thumb, raw meat should not sit at temperatures above 40 degrees Fahrenheit for more than 4 hours. 

First, check the fit of your pan or dish in the cooler. If it’s too wide to sit level inside the cooler, you can also use a small cutting board to lay the prime rib on top of the ice. 

To start, add ice to your cooler, but be sure to leave room for the rib roast. Now remove the prime rib from the freezer and transfer it to the roasting pan or cutting board. The rib roast should be vacuum sealed or placed in a leak-proof bag. 

Put the dish or cutting board full of rib roast into the cooler and close the lid. Defrost time in the cooler should be approximately the same as it would be in the refrigerator.

The Bath Method

A prime rib roast, or any large cut of meat or poultry, can be thawed in a cold water bath. No, not in the bathtub! That would be a sure way to upset your spouse or roommate. 

Rather, if you are pressed for time or forgot to pull the rib roast from the freezer early enough, you can defrost it in your kitchen sink or a large, clean container filled with cold water. A cold water bath will reduce thawing time to 30 minutes per pound. That’s only an hour and a half to 3 hours for the standard 3 to 6-pound prime rib roast. 

Whether you choose the sink or a large container such as a food grade 5-gallon bucket, sanitize it with mild soap and water, then rinse clean. Plug the sink if that is your chosen space. Take the prime rib from the freezer and, as with the ice chest method, make sure the roast is either vacuum sealed or in a leakproof bag. 

Gently set the frozen roast in the sink or container and add cold tap water. Add enough water to cover the rib roast completely. If your container is not deep enough to allow you to submerge the roast fully, you will have to rotate the roast every 15 to 20 minutes to ensure an even thaw. 

When defrosting in cold water, you should drain the container and add fresh water every 20 to 30 minutes to keep the thawing process in action. Ideally, you should only leave your prime rib in the cold water bath long enough to have thawed it all the way through. 

However, if you’re taking it immediately to the grill or smoker, it may be a good idea to bring it all the way to room temperature or around 72 degrees Fahrenheit. 

Insider Tips For Preparing Defrosted Prime Rib

Once your juicy rib roast is fully thawed, reserve some time to bring it to room temperature. Depending on the size of the prime rib roast, warming it up to room temperature could take 6 hours or more. 

Set your now-thawed rib roast on the counter until it reaches the target temperature. This is a great time to trim any fat that you’d like to remove or cut off the rib bones if your butcher hasn’t already done it for you. 

Cutting the rib bones away can also be done after cooking if you prefer. Give the prime rib another pat down with dry paper towels and coat it in your favorite seasonings. A simple salt, pepper, and garlic blend is always a safe bet. 

Coating the rib roast in a thin layer of butter will add to the savory flavor the beef naturally yields, and it will help the seasoning stick to the surface. As prime rib is traditionally served rare or medium rare, sear the entire outside by setting your roast on a high-heat flame for about 2 minutes on each side. 

Now it’s time to let it roast low and slow, preferably at 225 degrees Fahrenheit until the internal temperature of the rib roast reaches approximately 120 degrees Fahrenheit.

Freezing Prime Rib

Beef can actually be stored in the freezer for several months. So, even if you scored a great deal at your local grocery store during a sale, that freshness can stay locked in for over six months! 

how long to defrost prime rib

Likewise, if you manage to have any roast left over after that fantastic meal, you could seal it in a storage bag and freeze it for one of those nights that nobody wants to cook. Cooked beef will stay fresh in the freezer for just as long, and the smaller portions won’t take nearly as long to thaw!

Final Thoughts

With more significant portions of meat, such as a prime rib, allow plenty of time for it to defrost thoroughly. Then you can use the more straightforward option of leaving it in the refrigerator for a few days before your cookout. When the rib roast is thawed all the way through, it will cook more evenly, and you and your guests will enjoy this premium cut to the fullest.

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