For the Sauce: Combine all the ingredients (except for 1 tablespoon of the bourbon) in a medium saucepan and bring to a boil. Lower the heat to a simmer and cook until reduced by 1/3, stirring often. Sauce should be dark and slightly thickened (about 20 minutes). Turn of the heat and stir in the last tablespoon of bourbon. Sauce can be made up to 4 days ahead and stored in the refrigerator.
For the Ribs: Preheat the oven to 225º F. Remove the membrane from the back of the ribs. Slide a sharp knife under the white membrane on the back of the ribs and cut a hole into the membrane. Use your fingers to slide under the membrane and pull it away from the meat. Usually it helps to use a paper towel for extra grip. Remove all of the outer membrane and discard.
Pat ribs very dry with paper towels and cut each rack in half (to make them easier to turn later). Sprinkle a good tablespoon of dry rub on each side of the ribs and press until it’s well-coated all over. (you should use about 4 tablespoons for 2 whole racks).
Lay a large piece of foil on a baking tray and place one rack on it, meat-side up. Fold up 3 sides of the foil to create a rim: pour half the apple juice into this pocket and then fold over and crimp the packet closed. Wrap the packet in a 2nd layer of foil. Repeat with the second rack. Cook for 4 to 4 1/2 hours. The ribs are ready when you can pierce them easily with a fork. Remove the ribs from the oven and set aside. Unwrap the ribs carefully and place them on a baking tray, meat side up. (Ribs can be par-cooked the day ahead and refrigerated at this point. If making the day ahead, let the ribs cool for 20 minutes, then take them out of the foil and place in sealable bags and refrigerate overnight. Let them come to room temperature before the next step).
Note: Ribs can be finished in the oven or on a grill. Turn the broiler on high (or prepare a grill with medium-high heat) and set an oven rack about 6 inches from heat. Coat the the ribs well with BBQ sauce. Place the ribs under the broiler or on grill and cook until the sauce just starts to bubble (4-5 minutes). Take them out and apply another coat of glaze and cook again until glaze bubbles and browns (Do not walk away while broiling! They can burn easily so watch carefully). Remove from the broiler or grill, cut the ribs and serve.