Marinating Prime Rib Roast: How Long Is Too Long?

A prime rib roast is a popular choice for a holiday dinner, but it's not a cheap cut of meat, so it's important to cook it properly. The cooking time will depend on how you like your meat cooked, but as a rule of thumb, you should allow for 15 minutes per pound. In terms of how long to marinate the meat, most recipes suggest a minimum of six hours, but preferably leaving it overnight (around eight to 12 hours) for the best flavour.

Marinating a prime rib roast overnight

Ingredients

• 1 (10-pound) prime rib roast
• 10 cloves of garlic, minced
• 2 tablespoons of olive oil
• 2 teaspoons of ground black pepper
• 2 teaspoons of dried thyme
• 1/2 small white onion
• 2 tablespoons of rosemary (fresh)
• 2 tablespoons of thyme (fresh)
• 4 tablespoons of Worcestershire sauce
• 1 teaspoon of spicy Dijon mustard
• 1/4 teaspoon of black pepper

Method

Firstly, gather all the ingredients for the marinade. Mix the garlic, olive oil, salt, pepper, and thyme together in a small bowl. Place the roast in a roasting pan with the fatty side up. Spread the mixture over the top of the roast and let it sit at room temperature for no longer than 1 hour.

Next, preheat the oven to 500 degrees Fahrenheit. Bake the roast for 30 minutes, then reduce the temperature to 325 degrees Fahrenheit and continue roasting for an additional 60 to 75 minutes. The internal temperature of the roast should be 135 degrees Fahrenheit for medium-rare.

Allow the roast to rest for 10 to 15 minutes before carving so that the meat can retain its juices. This recipe yields 15 servings.

It is important to note that the marinade should be applied to the roast the day before cooking. This allows the roast to marinate overnight, enhancing the flavour.

Alternative Marinade

For a red wine marinade, place the meat in a self-sealing plastic bag set in a shallow dish. For the marinade, in a small bowl, stir together wine or broth, onion, water, lemon juice, Worcestershire sauce, rosemary, marjoram, and garlic salt. Pour the marinade over the meat, seal the bag, and refrigerate for at least 6 hours or up to 24 hours, turning the bag occasionally.

Cooking

After marinating, drain the meat and discard the marinade. Place the meat, fat side up, in a large roasting pan. Insert a meat thermometer into the centre without touching the bone.

Roast in a 325-degree Fahrenheit oven to the desired doneness. Allow 2 to 2-1/2 hours for rare or 2-1/4 to 3-1/4 hours for medium. Transfer the meat to a cutting board, cover with foil, and let stand for 15 minutes before carving.

The temperature of the meat will rise by about 5 degrees during this standing time. If desired, garnish with additional fresh rosemary.

How to prep a prime rib roast before marinating

Preparing a prime rib roast can be a simple process, but it's important to get it right to ensure the best flavour and texture. Here is a step-by-step guide on how to prep a prime rib roast before marinating:

Firstly, source a good-quality prime rib roast from your butcher or grocery store. Ask your butcher any questions you may have to ensure you get the best cut for your budget. While "prime" is in the name, this actually refers to the “primal rib”, a cut of beef, and not necessarily the USDA grade.

Next, give your roast a quick rinse with cold water and pat it dry with paper towels. You can then place it in a roasting pan or sheet pan, ensuring it is fat-side up.

If you want to add extra flavour, you can stud the roast with garlic. Using the tip of a small knife, poke several 1-inch deep slits randomly over the roast. Cut 2-3 garlic cloves into 6-8 lengthwise slivers and tuck the slivers into the slits.

Now it's time to make your marinade. In a small bowl, mix together your chosen liquids (such as dry red wine or beef broth), chopped onion, and any other seasonings (such as rosemary, marjoram, garlic, salt, and pepper). Give it a good stir to ensure everything is well-combined.

Take the marinade and rub it all over the roast, making sure to coat the surface evenly. You can use your hands to really get in there and give it a good coating.

Finally, cover the roast with plastic wrap and place it in the refrigerator to marinate. It's best to leave it overnight (at least 8 hours) to allow the flavours to really penetrate the meat.

And that's it! Your prime rib roast is now prepped and ready for cooking. Don't be tempted to skip the overnight marinating step, as this makes a big difference in the final flavour of the meat.

The best ingredients for a prime rib roast marinade

A prime rib roast is a great choice for a holiday dinner or a special occasion. While the roast itself is a star, a good marinade can make it even better. Here are some of the best ingredients to use for a prime rib roast marinade:

Liquids

A good marinade needs a base liquid to help carry the flavours. For prime rib, dry red wine or beef broth are excellent choices. You can also add a little water, lemon juice, and Worcestershire sauce to boost the flavours.

Onion

Onions are a versatile ingredient that can add depth and sweetness to your marinade. You'll need about 1/2 cup of chopped onion, and any type of onion will work. If you prefer, you can also use shallots.

Seasonings

When it comes to seasonings, fresh rosemary is a popular choice for prime rib. You can also use dried rosemary if fresh is not available. In addition, dried marjoram and garlic salt will enhance the flavour of the roast.

Olive oil, garlic, and thyme

For a tasty and versatile marinade, try a combination of olive oil, garlic, and thyme. This trio of ingredients works well with prime rib and can also be used for tri-tip roast and brisket.

Salt and pepper

Don't forget the basics! Salt and pepper are essential for enhancing the natural flavours of the meat. Use Kosher or coarse sea salt and freshly ground black pepper for the best results.

Remember, the key to a successful marinade is to give it enough time to work its magic. Be sure to plan ahead and allow your prime rib to marinate overnight or for at least several hours before cooking.

How long to cook a prime rib roast

The cooking time for a prime rib roast depends on the weight of the meat, the desired level of doneness, and the cooking temperature.

Cooking time based on weight

A general rule of thumb is to cook the prime rib roast for 15 minutes per pound of meat. For example, for a 12-pound roast, the total roasting time should be around 180 minutes or 3 hours.

Cooking time based on doneness

The cooking time also depends on whether you want your meat rare, medium-rare, or medium-well.

For rare meat, cook for 10-12 minutes per pound. The internal temperature should reach 120-125°F.

For medium-rare meat, cook for 13-14 minutes per pound. The internal temperature should be 130°F.

For medium meat, cook for 14-15 minutes per pound. The internal temperature should be 135-140°F.

For medium-well meat, cook for 14-15 minutes per pound. The internal temperature should be 145-150°F.

It's important to note that the meat will continue to cook and the internal temperature will rise by about 5-10°F while it rests after being removed from the oven. Therefore, it is recommended to remove the roast from the oven when it is 5-10°F away from your desired temperature.

Cooking time based on temperature

Most recipes recommend cooking the prime rib roast at a high temperature of 450-500°F for the first 15-30 minutes and then lowering the temperature to 325-350°F for the remaining cooking time.

Resting time

After removing the prime rib roast from the oven, it is crucial to let it rest for at least 15-20 minutes before carving. This allows the juices to settle, making the meat juicier and more tender.

In summary, the total cooking time for a prime rib roast depends on various factors, but the general guideline is around 15 minutes per pound of meat. Adjustments should be made based on the desired level of doneness, with rare meat requiring less cooking time and medium-well meat needing more. Always use a meat thermometer to monitor the internal temperature and remember to account for the additional rise in temperature during the resting time.

How to serve a prime rib roast

A prime rib roast is a great choice for a special occasion or holiday dinner. It's a delicious and crowd-pleasing meal that can be served in a variety of ways. Here are some tips on how to serve a prime rib roast perfectly:

Choosing the Right Cut:

Start by selecting the right cut of meat. Prime rib roasts are typically sold as either "first cut" or "second cut". The first cut is closer to the loin end of the rib and is more tender, while the second cut is closer to the shoulder and is fattier and more marbled. Choose the one that prioritises tenderness or flavour, depending on your preference.

Planning the Portions:

As a rule of thumb, one rib bone serves two people. So, for example, a 12-pound roast with five ribs would serve around 10 people. However, it's always better to have too much than too little, so consider the appetites of your guests and plan accordingly.

Marination:

To enhance the flavour of your prime rib roast, don't skip the marination step. Mix salt, pepper, garlic, herbs, and olive oil, and rub the mixture all over the roast. Cover it with plastic wrap and let it marinate overnight in the refrigerator. This step will make a significant difference in the overall taste of the dish.

Cooking the Roast:

Take the roast out of the refrigerator about two hours before cooking to bring it to room temperature. Preheat your oven to 450°F (230°C) and place the roast on a lower oven rack. After 30 minutes, add half a cup of water to the bottom of the roasting pan to prevent the drippings from burning and smoking.

Rotate the roast and cook for another 30 minutes until it starts to brown. Adjust the positioning of the roast if one side has more fat and needs to be browned. Once browned, lower the heat to 350°F (175°C) and continue roasting for 90 to 120 minutes.

Resting and Serving:

After roasting, let the prime rib rest on a cutting board or serving platter, covered loosely with aluminium foil, for about 20 minutes. This allows the juices to redistribute and ensures a juicy and tender roast. Then, slice and serve the prime rib immediately.

Sides and Accompaniments:

Prime rib is best served with a variety of side dishes. Here are some options:

• Potatoes: Mashed potatoes, scalloped potatoes, baked potatoes, or roasted baby potatoes are all excellent choices. You can also add ingredients like butter, cream, chives, or cheese to elevate the flavour.
• Vegetables: Roasted Brussels sprouts, asparagus, broccoli, or carrots make great sides. You can also try air-fried or balsamic vinegar-glazed Brussels sprouts for a crispy and flavourful option.
• Salads: A fresh salad can balance out the hearty roast. Try a spinach salad with strawberries and pine nuts, a Brussels sprout salad with almonds and pomegranate seeds, or a classic Caesar salad.
• Bread: Freshly baked rolls or biscuits are a great addition to the meal. You can also try herb focaccia or cheese bread for extra flavour.
• Other sides: Other options include creamed spinach, roasted cauliflower, green beans, or a variety of casseroles.

Leftovers:

If you have any prime rib leftovers, don't worry! Thinly slice the meat and use it for sandwiches the next day, or get creative and add it to dishes like Instant Pot pho, steak and egg hash, or creamy steak fettuccine.

Frequently asked questions