Mix together the coffee, salt, paprika, chile powder, dark brown sugar, oregano, garlic powder, onion powder, black pepper, coco powder, and coriander in a small bowl to make the rub.
Remove the membrane from the back of the rack, and trim the ribs. Rub each rack liberally with the rub. Wrap ribs in foil or place in a large container and store in the refrigerator over night (optional).
Remove the ribs from the fridge while preparing the smoker. Fire up the smoker to 225°F, adding a few chunks of smoking wood chunks when at temperature. When the wood is producing smoke, place the ribs in the smoker, meat side up, and smoke until the ribs have a slight bend when lifted from one end, about 5-6 hours. If using sauce, brush on the sauce and continue to cook until sauce has caramelized, about 15-20 minutes longer.