I'm not sure if it's the whiskey, the rub, the insertion of flavorings in the center of the rub or the bacon wrapping that does it, but I assure you this will be by far the best pork loin you've ever tasted.
3 tablespoons Tennessee whiskey (may substitute with other whiskey)
4 tablespoons Julian's BBQ Rub or any reasonable facsimile
3 tablespoons Dijon mustard
1/2 cup packed brown sugar
4 slices bacon
2 cups of wet hickory wood chunks (optional)
3 tablespoons salted butter
3 tablespoons brown sugar
3 tablespoons Dijon mustard
3 tablespoons Tennessee whiskey
If you haven't already done so, make a batch of my BBQ Rub and set aside.
Make the glaze by combining the butter, brown sugar, mustard, and whiskey in a saucepan and boil until thickened, about 5 minutes. Remove from heat and set aside.
Using a sharp knife, cut the roast almost in half lengthwise through one side (stop about 1 inch from the opposite side). Open the roast up as you would a book. Sprinkle the inside of the roast with 1 tablespoon of the whiskey and let it marinate for 5 minutes. Sprinkle a 1 tablespoon of the rub over the inside of the roast. Spread the mustard on top with a spatula, then sprinkle the brown sugar on top of the mustard. Sprinkle the remaining 2 tablespoons of whiskey on top of the brown sugar. Fold the roast back together and sprinkle 2 tablespoons of rub over the outside.
Cut four 12-inch pieces and one 18 inch piece of butcher's string. Position the 12-inch pieces of string on the work surface so that they are parallel and roughly 2 inches apart. Lay the last string across the four short strings at their center. Place a slice of bacon across the long string so that it will run the length of the roast from end to end. Don't worry if the bacon is longer than the roast.
Set the roast on top of the bacon about in its center. Place a slice of bacon on top of the roast. It may hang down the sides. Press the remaining 2 slices against the long sides of the roast. Use toothpicks to temporarily hold them in place until the string is attached. Tie each piece of string together around the roast so that they hold the slices of bacon against it. Tie the long string capturing and holding in place the bacon that was longer than the roast, so you have a moderately tight package. Remove the toothpicks and sprinkle the remaining rub as needed to fully cover the roast. Set aside.
Set up the grill for indirect grilling and preheat to medium. If using a gas grill, place all of the wood chips or chunks in the smoker box or in a smoker pouch, and run the grill on high until you see smoke; then reduce the heat to medium. If using a charcoal grill, place a large drip pan in the center, preheat the grill to medium, then toss all of the wood chips or chunks on the coals.
When ready to cook, place the pork roast on the hot grate away from the heat, and cover the grill.
Start basting the roast with the glaze after 30 minutes, and continue basting every 15 minutes. If you are using a charcoal grill and the pork is not done after 1 hour, you'll need to add 12 fresh coals to each side.
Cook the pork for 1 to 1-1/2 hours. Insert an instant-read meat thermometer into the center of the roast to test for doneness, which should be about 160F degrees.
Transfer the cooked roast to a cutting board with a juice reservoir and let it rest for 10 minutes. The juices should run clear and be captured for use in the glaze. Pour off any juice and stir into the remaining glaze.
Remove and discard the strings. Slice the roast crosswise and drizzle the remaining glaze over it.