Remove the pork loin from its packaging and wipe it dry with paper towels. Place, skin side down, in slow cooker.
In a medium bowl, whisk together the barbecue sauce ingredients. Pour over the pork loin and use your hands to make sure the pork is well-coated.
Cover and cook on low for 8 hours.
Carefully remove the slow cooker lid (hot steam will escape). Increase heat to high. Use two forks to shred the pork and mix it well with the sauce. Allow to cook a few more minutes until thickened, then serve.