Your oven does a fine job of cooking large roasts, but it can't match the rich flavor of a roast cooked at an open fire. If you don't have a charcoal kettle or barbecue pit at your disposal, you can use an open fire to cook roasts such as prime rib. It's easiest if you have a rotisserie spit to turn the roast, so it cooks evenly, but all you really need is a campfire and some patience.
Trim away any excess fat from the roast's surface. Season the roast all over with salt and pepper, or use a dry spice rub or paste if you prefer. Rest the seasoned roast for at least an hour or two, and preferably overnight if possible.
Arrange a firepit with a line of stones or large logs on either side to trap some of the fire's heat. Keep one end narrow enough to fit a wire rack, and build a fire of dry hardwoods or charcoal at the other end. Let it burn down to coals, then rake the bed of coals to the middle. Keep a few fresh pieces of wood at the back of the fire to replenish your bed of coals as you cook.
Slide a pan under the rack to catch drips from the roast, then position the prime rib over it. It should be far enough from the coals to only receive indirect heat, but close enough for the meat to cook gently. if your roast is sizzling and beginning to brown after 30 minutes, move it farther away. If it isn't visibly cooking, move it closer.
Slow-roast the beef in the indirect heat of your fire for 4 to 6 hours, depending on the size of the roast, until its internal temperature reaches 115 degrees Fahrenheit when tested with an instant-read thermometer. Turn the beef every 20 to 30 minutes during this cooking time, to ensure it cooks evenly.
Using a pair of long tongs, move the roast to the high-heat area over the coals. Finish it in the searing heat, turning it to brown the outside deeply. Remove the roast from the fire, and let it rest for 10 to 15 minutes before carving. The final temperature should be 130 F for medium rare, or higher if you prefer your beef more done.
Season the prime rib roast with your favorite spice paste or dry rub, and refrigerate it overnight.
Build a fire of hardwoods or charcoal, taking care to remove any flammable materials from the immediate area. Let the fire burn down to coals, keeping a supply of additional firewood or charcoal nearby to replenish the coals from the back as needed.
Find the roast's center of balance by turning it in your hands a few times, then skewer it with the spit. Use the rotisserie's secondary forks or prongs to fix the beef in place, and rotate the spit a few times to check the balance. Adjust the roast's position if necessary.
Position the rotisserie roughly 18 to 24 inches in front of the coals, then lock the spit into the rotisserie frame. If it has an electric motor, plug in the motor and turn it on. If it's a manual model, start turning the crank slowly and make sure you have lots of helpers lined up to take a turn. Place a pan under the roast to catch drips.
Slow-roast the prime rib for 4 to 6 hours, or until it reaches your preferred degree of doneness. A large roast will continue to cook for several minutes after it comes off the spit, so take it from the heat when the internal temperature is still 10 degrees below the doneness you want.
Items you will need
- Spice paste or dry rub
- Seasoned hardwood or charcoal
- Drip pan
- Instant-read thermometer
If the ribs feel loose and wobbly before you cook the beef, tie them tightly to the roast with butcher's twine. Alternatively, for easier cooking and carving, trim off the ribs to create a boneless ribeye. Tie it tightly with twine to give it a cylindrical shape, so it cooks evenly. Slow-cook the ribs separately, either at the same meal or for a second meal.
The drippings in the pan under your roast make a wonderful jus to serve with the beef. Pour them into a narrow measuring cup and ladle off the fat as it rises to the surface, then serve the intensely flavored juices on the side.
Roasting prime rib over an open fire is much like cooking one in your charcoal kettle, though it takes longer because there's no lid to trap the heat.
If you have a traditional indoor fireplace, many companies manufacture rotisserie spits that fit neatly on your hearth. This is ideal for roasting your beef in inclement weather.