Preheat Grill: follow instructions for your particular grill or smoker to preheat to 225℉.
Prepare Meat: Trim the meat if needed, typically it comes trimmed.
Remove the membrane from the back, simply peel up a corner with your fingers (the skin with a silver shine to it) and using your hands, peel the layer of membrane off the bones.
Binder: place the meat on a large baking sheet, meat side facing up. Brush the mustard over the meat. Then flip the ribs and brush mustard on the back side of the ribs also.
Season: Evenly sprinkle the sweet rub over the back of the ribs, then carefully flip and do the same to the top of the ribs. Press the rub into the mustard to help ensure the rub stays on the meat.
Smoke: Place the ribs on the grill so that the meat part is facing up, the bones are on the bottom. Smoke at 225℉ for 2 hours undisturbed. After 2 hours, spritz the ribs with the apple cider vinegar (or diluted apple juice) every 30 minutes for the next hour. (3 hours total on the smoker at this point..spritzing twice)
Slather: Flip the ribs, so the meat side is down and bone side is up, spritz the ribs, then brush the BBQ sauce on the ribs, close the smoker and let this cook for 15 minutes. Then flip the ribs so that the meat side is up, spritz the ribs again and brush the remaining sauce on the top of the ribs, close the smoker and let this cook another 15 minutes.
Wrap: Remove the ribs from the smoker and wrap tightly in aluminum foil. Easiest method is to lay a sheet of foil flat on a large baking sheet, lay the ribs on this, fold the edges in over the ribs, then use another sheet of foil over the top. This helps ensure that the juices stay inside the foil and don’t leak out the bottom.
Continue Cooking: Place the ribs back on the smoker (or in an oven at 225℉, at this point we have the smoke flavor, we’re just braising the meat). Continue to cook the ribs at 225℉ for another 2 hours.
Set Sauce: Remove the ribs from the foil and place the ribs back on the grill. Smoke for an additional 30-45 minutes until the ribs are done. (careful opening the foil, there will be a lot of liquid in there. Carefully remove the foil packets to a large baking sheet and open and remove the ribs there, this helps contain the liquid that will spill out).
Rest: once done cooking, test for done-ness (information below), remove the ribs from the smoker and place on a clean baking tray. Cover tightly with foil and let the ribs rest for at least 30 minutes before serving. (Smoke Pork Ribs at 225 degrees F until the ribs reach an internal temperature of 203 degrees F.)