When it comes to smoking meat, 250 degrees may be the most popular heat amongst pitmasters. Cooking prime rib low and slow at 250 degrees turns out wonderfully, and it’s easy to hold that temperature. But how long to cook prime rib at 250 degrees Fahrenheit is more challenging than you think.
How Long to Cook Prime Rib at 250?
Prime rib is a naturally tender cut of beef when it’s properly cooked to medium rare. The process will take 25 to 30 minutes per pound at 250 degrees. A 3-bone prime rib weighs about 7 pounds, so you should allow 3 to 3.5 hours of cooking time.
The average weight of prime rib sold in grocery stores is 4.5 to 8 pounds for bone-in and 3 to 5 pounds for boneless. On the heavier end, that’s enough to feed up to 9 or 10 people. You can get custom cuts of prime rib from a local butcher if the supermarket doesn’t have the right size at the time.
Planning ahead is crucial when it comes to smoking meats. It may take upwards of 7 hours or more, including pre-cook preparation, to complete a prime rib. That’s an average of 3 hours to set out, 3 hours to cook, and 30 minutes to rest.
What You Need To Know About Prime Rib
Prime rib gets its name from the butchering process rather than necessarily being graded as prime. It’s a primal cut, meaning that it’s one of the first cuts to be removed by the butcher. Once the rib cage is removed from the carcass, it’s trimmed into smaller cuts like plate ribs, short ribs, and our favorite, prime rib.
Supermarkets and online delivery services sell prime rib in a wide selection of sizes. The supermarket prices may be the lowest, but you’ll get higher quality beef from online services and independent butchers.
You can get bone-in or boneless prime rib. However, once the rib bones are cut away, you get what’s called a standing rib roast. Bone-in prime rib is our go-to choice when it’s going on the smoker.
The rib bones of a rib roast offer protection from overcooking, but they are generally removed prior to serving.
Ask your butcher if they can cut the bones off and tie them back onto the roast. This way, you still get the benefit of cooking bone-in, and afterward, simply cut the twine that binds to remove the ribs easily.
Before the Cooking Begins
Take your prime rib from the refrigerator and set it out at room temperature for 2 to 4 hours. This allows the center of the roast to warm up a bit. A well-acclimated prime rib will cook to a consistent temperature throughout the roast.
This is the perfect time to trim and season the rib roast. You shouldn’t have much if any, fat to trim away. A thin layer is all that’s needed since there’s a large fat cap against the rib bones, and the meat is usually marbled.
Generously cover the rib roast with a blend of salt, pepper, garlic, or your favorite BBQ seasoning. Don’t be shy! This large cut of meat can handle it. Another option is to coat the prime rib in butter before applying the seasoning.
Sear the Steer
There are several ways to sear a prime rib. Skipping this step could be the difference between a mediocre prime rib and a best-ever one. Pan searing is an easy option, as well as reverse searing on your smoker.
Reverse searing is nearly effortless when done on the smoker. All you have to do is raise the temperature to about 500 degrees until the outside of the rib roast sizzles for a couple of minutes. You can also do this on the firebox if your smoker has a grill grate in it.
Conversely, searing at the beginning of cooking will capture loads of delicious smoky flavor and create a nice bark. A crispy bark goes a long way to balance out the meal. About 2 minutes on each side is all you’ll need before adjusting the smoker to 250 degrees.
Setting Up the Smoker
We like to place a drip pan under the grate in the smoker before starting the rib roast. The meat drippings can be used afterward to make an au jus sauce. This is an excellent accompaniment to prime rib.
A variety of hardwood species provide great choices for smoking a prime rib;
- Pecan
- Maple
- Apple
- Oak
- Hickory
You can also blend different types of wood to get the best characteristics of each one.
You won’t have to do much but wait during the first half of cooking the prime rib. At the halfway point of your estimated cooking time, begin monitoring the internal temperature of the rib roast. A meat thermometer should be kept close at hand for this purpose.
How to Know When Prime Rib is Done
Once the prime rib reaches the target temperature, remove it from the smoker and allow it to rest for 15 to 30 minutes. Look for an internal temperature of 124 to 129 degrees before pulling the rib roast from the smoker. The temperature will continue to increase by 5 to 10 degrees while it is resting.
During the resting process, the meat fibers will reabsorb some of the juices. For that reason, it’s essential to wait for the prime rib to finish resting. Many BBQ enthusiasts will tent the prime rib with aluminum foil or butcher paper while it’s resting. This traps the heat and helps tenderize the meat.
Presenting the Prime Rib
Remove the ribs that have been tied onto the roast to make carving easier. The discarded rib bones can be used for recipes later.
Rib roast should be sliced vertically to a thickness of about half an inch. Family members and guests who prefer their beef to medium may want the first outer slices. The outer extremes of the roast will be more done than the inner slices. However, the outer cuts tend to dry out faster.
Prime rib will be the focal point of dinner. Depending on the occasion, you may want to serve the prime rib plainly and quickly or dress it up some. Add a slice of prime rib to a plate and garnish it with fresh herbs. Include a cup of au jus and some hearty vegetables, and you’ll have a meal fit for a king!
Wrapping it Up
Prime rib is an excellent meal when it’s smoked slow and low. Smoking at 250 degrees is a sure way to showcase the flavor and tenderness that rib roast offers. And 3 hours of cooking time is definitely worth the wait!
