1. Preparing the meat. Using a paper towel, remove the membrane from the back side of the ribs that runs along the bones. Trim any excess fat from the sides. Season the ribs generously on all sides and allow them to rest for at least 15 minutes, up to overnight.
2. Smoke the ribs for 90 minutes at 300°F. Place the ribs in the smoker with the meat facing up. Allow them to cook undisturbed.
3. Prepare the mop sauce. Place the butter, hot sauce, Worcestershire sauce, and thyme in a saucepan over medium heat. Melt everything together and stir to combine. Keep this sauce handy for the mopping phase. Add additional hot sauce as desired.
4. Apply the mop sauce after the first hour. Using a pastry brush or basting mop, gently add some of the mop sauce to the top of the ribs. There should be more than half left after this application, which will be used next. Continue to cook the ribs for the full 90 minutes.
5. Wrap and braise the ribs for 45 minutes. Remove the ribs from the smoker. Lay out 2 sheets of heavy-duty foil onto a counter. Place a rack of ribs meat-side down. Pour some of the mop sauce along the sides and top of the rack. Wrap the foil layers tightly around the ribs, crimping the edges so the seam is on the top. Repeat this for each rack, and place them back in the smoker for 45 minutes.
6. Rebuild the bark. Open up the foil where the seam was crimped on the top. Using tongs, carefully flip the ribs so the meat is exposed. If there are any bald spots, sprinkle additional seasoning on those. Cook for another 15-20 minutes until the bark has firmed up and they are cooked to your liking. The meat temperature will be about 208-210°F.
7. Slice and serve. Allow the ribs to rest for a few minutes before slicing between the bones. Keep as much of the juices from the foil as possible to pour over the ribs when serving.

Notes