Covering with foil for part of the cook is a normal part of the process, as far as I am concerned. When I do baby back ribs, I cook them uncovered for 2 hours, foiled for 1 hour and uncovered for another hour or so until they are done. They come out tender and juicy and with a bit of chew left in them. Not quite falling off the bone. I like them to feel like meat. And I use a combination of apple and pecan smoke with my own rub.