Mix the spices together in a small bowl. Reserve ¼ cup of the spice rub and set aside for a second application.
Rub the remaining spice mixture over the pork shoulder. Place the shoulder into a bag and add the liquid smoke, if using. Seal with a vacuum sealer.
Place in a water bath and set the timer for 18-24 hours. Cover the container with foil or plastic wrap to reduce water evaporation.
After an 18-24 hour period, remove the pork shoulder from the vacuum-sealed bag and pat dry with paper towels.
Rub the remaining spices over the cooked pork shoulder.
Preheat oven to 400°F. Place the pork shoulder in a roasting pan and cook for 30 minutes, or until the spices have developed into a dark crust.
Use two forks to shred the pork, then serve.
Notes
This recipe will give you fall-apart tender pulled pork. For pork shoulder that can be sliced, set the induction cooker to 145°F.Because of the long cook time, it is recommended to use a vacuum-sealed bag instead of the water displacement method. This will help reduce the risk of leaks.If the pork is not fall apart-tender when you remove it from the sous vide, it can be placed in a 300° oven for up to 90 minutes.