Remove slabs from smoker. Place each slab, meat side down, on a large piece of heavy-duty aluminum foil. (Foil should be large enough to completely wrap slab.) Bring up edges of foil to contain liquid. Pour half of Rib Braising Liquid over each slab. Tightly wrap each slab in foil. Return slabs, meat sides down, to smoker. Cook, covered with lid, 1 to 1 1/2 hours, checking for tenderness after 1 hour.