Preheat grill or smoker according to directions to 225℉.
Trim the pork shoulder. Removing portions of the fat cap, so that it is only approximately 1/4 of an inch thick. Then score the fat, cutting a grid pattern into the fat cap, cutting just enough to get through the fat to the meat.
Slather the entire pork shoulder with mustard, as a binder.
In a small bowl combine the ingredients for the rub: salt, pepper, garlic powder, and paprika. Stir together.
Evenly sprinkle the rub over the entire pork shoulder. Press the rub into the mustard before turning the pork over to sprinkle the other side.
Place the pork in the center of the smoker or the grill on the grate. Insert probe to monitor the temperature.
In a spray bottle combine the apple cider vinegar and water. Shake to combine.
Smoke for 2 hours before opening smoker. At this point open and spritz the pork, continue spritzing the pork every hour until the pork reaches an internal temperature of 160℉. This helps with the creation of the smoke ring and keeps humidity in the smoker.
Once the pork reaches an internal temperature of 160℉ wrap using foil or peach paper. Place back in smoker to continue cooking.
Cook until pork reaches an internal temperature of 195-205℉. Depending on the texture of pork you prefer will determine when you will want to pull off. At 195 pork is more moist but less tender, more string. At 205 pork is more tender, more chunky than stringy, but less moist. Any temperature in this range will yield great pulled pork!
Once internal temperature is reached, pull from the smoker, make sure the pork is wrapped nice and tight. Let rest for 1-2 hours before shredding. Store in a clean empty cooler, or in a turned off oven.