Step 1

Cut the pork shoulder into 2-inch cubes.  Add the pork to the bowl of the slow cooker.

Step 2

Add the chipotles in adobo, pineapple, red onion, chili powder, lime juice, white vinegar, salt, cumin and black pepper to a blender or food processor.  Puree until the mixture is completely smooth, about 30-60 seconds.  Stir in the beer until it is evenly combined.  Then pour the mixture on top of the pork, and toss until the pork is evenly coated.

Step 3

Cook on low for 8-10 hours, or on high for 4-5 hours, until the pork is completely tender and shreds easily with a fork.  Use two forks to shred the pork, then toss it in the remaining juices.

Step 4

Serve warm on tortillas, garnished with optional toppings.