Combine the water, apple cider, tomato sauce, brown sugar, Better Than Bouillon, Worcestershire sauce, Crystal hot sauce, soy sauce and liquid smoke together in the bottom of the slow cooker. Stir until the brown sugar is completely dissolved.
Quarter the onions and arrange the pieces on the bottom of the slow cooker. Set the temperature to low.
In a small bowl, combine chili powder, cumin, smoked paprika, garlic powder, onion powder, sea salt and cayenne pepper. Apply the dry rub liberally to all sides of the ribs.
Carefully arrange the ribs in the slow cooker on top of the onions, meat side up. Cover and cook on low for 7 to 8 hours.
Pre-heat oven to 350 degrees F. When ribs are done, carefully remove from the slow cooker. Place ribs on a parchment-lined baking sheet and allow to rest at room temperature for 5 minutes. Evenly apply the Birch Beer Barbecue Sauce to the ribs using a spoon or pastry brush.
Transfer the ribs to the pre-heated oven and bake for 10 minutes. Apply a second, thin layer of Birch Beer BBQ Sauce and continue cooking for about 5 minutes, or until sauce reaches desired color and doneness.