Remove membrane (strip of white fat) from the back of the ribs; discard. Sprinkle all sides of pork ribs generously with BBQ spice rub of your choice. Let marinate in the refrigerator for several hours or overnight.
Place seasoned pork ribs and liquid smoke in a vacuum sealer plastic bag or in a freezer zip-lock baggie. If using a zip-lock bag, use the water displacement method to remove the air from the bag. If using vacuum bag, use vaccum sealer to remove air.
Prepare the sous vide by setting the temperature to 165 degrees F. Place ribs in the water, and be sure the meat is completely submerged.
Cook BBQ pork ribs for 12 hours in the sous vide machine.
Once done cooking, place the bag of pork ribs immediately into a bowl with ice (ice bath) until completely chilled.
To finish pork ribs, remove from the plastic bag, and pat dry with paper towels.
Arrange the pork ribs on an aluminum foil-lined sheet pan or large baking sheet pan, and season both sides again with another layer of spice rub.
For a dry rubbed pork rib, see the notes below.For a sauced BBQ pork rib recipe, bake the pork ribs at 300 degrees F for 20 minutes. Meanwhile prepare homemade BBQ sauce by whisking together ketchup, water, yellow mustard, plain vinegar, onion powder and Worcestershire sauce in a large bowl.
Baste the ribs in the sauce at the 20 minutes mark, and continue adding layers of BBQ sauce every 5 minutes for approximately 20-25 additional minutes of until the ribs are sticky.