Preheat the smoker to 225ºF. Use your favorite wood chips; we like apple wood chips for this.
Use a sharp knife to cut the membrane off the bottom of the ribs. This can be really tough if you cook it and is much better being removed--once removed, the flavors can soak into the actual meat much better.
Brush the ribs all over with mustard and then sprinkle on the barbecue spice. Place the ribs bone side down in the smoker and smoke for 3 hours. It’s a good idea to spritz them throughout the cook time with apple juice or water to keep them moist.
Bring the ribs out and allow them to cool a little until you can handle them. Mix the apple juice and half the barbecue sauce together then make a boat with aluminum foil and place the ribs inside. Pour over and seal the foil.
Place the wrapped ribs in the smoker again and smoke for another 2 hours.
After 2 hours remove the ribs and unwrap the foil. Coat the ribs in the rest of the barbecue sauce and then place them back into the smoker to smoke for the last hour.