Prepare the ribs and rub: Remove the thin, papery skin from the back of each rack of ribs by pulling it off in a sheet with your fingers, using the corner of a kitchen towel to gain a secure grip, or with pliers.

Combine paprika, black pepper, brown sugar, salt, celery salt, cayenne, garlic powder, dry mustard and cumin in a small bowl. Whisk to mix. Rub two thirds of mixture over both sides of ribs, then transfer ribs to roasting pan. Cover and let cure, in the fridge, for 4-8 hours.

Prepare mop sauce (if using): Mix together cider vinegar, mustard and salt in a bowl. Set aside.

Set up grill for Indirect method and place a large drip pan in the centre. Preheat to medium.

When ready to cook, toss chips or chunks onto coals. Brush & oil the grill grate. Arrange ribs on the hot grate over the drip pan. Cover the grill & smoke ribs for 1 hour.

When ribs have cooked for an hour, uncover grill and brush ribs with mop sauce (if using). Replace cover and continue cooking until tender and almost done (15-30 minutes longer for baby back ribs and 30-60 minutes longer for spareribs). The ribs are done when the meat is very tender and has shrunk back from the ends of the bones.

15 minutes before the ribs are done, season them by sprinkling on the remaining rub.

Serve racks cut in half or whole.