The “dry rub” rib, which is unique in the annals of American barbecue, contains paprika, chili powder, oregano, and mustard. Unlike most American barbecue rubs, it’s not in the least bit sweet.
Step 1: Set up your grill for direct grilling and preheat to medium low. Ideally, you’ll be using a charcoal grill stoked with Royal Oak natural charcoal.
Step 2: Place a rack of ribs meat side down on a baking sheet. Remove the thin, papery membrane from the back of the rack by inserting a slender implement, such as a butter knife or the tip of a meat thermometer, under it. The best place to start is on one of the middle bones. Using a dishcloth, paper towel, or pliers to gain a secure grip, peel off the membrane. Repeat with the remaining rack.
Step 3: Generously season the ribs with salt and pepper. Arrange the ribs on the grill grate, bone side down, and grill until sizzling and golden brown, 20 to 30 minutes. Turn the ribs and grill meat side down until sizzling and golden brown, 20 to 30 minutes more. The dripping fat may cause flare-ups — if this happens, move the ribs to another spot on the grate to let them die down.
Step 4: Meanwhile, make the rub. Place the spices and seasonings in a bowl and stir to mix. Note: this may give you more rub than you need — don’t worry, you’ll find plenty of other uses for it.
Step 5: Make the mop sauce. Place the water, vinegar, salt, and rub in a bowl and whisk until the salt crystals are dissolved.
Step 6: When the ribs are cooked, transfer them to a cutting board. Generously brush or mop the ribs on both sides with mop sauce. Thickly sprinkle the meat side with rub to form a 1/8th inch thick crust. Cut each slab in half (or serve whole), with any remaining rub on the side.