Prepare The Baby Back Ribs. Rinse and pat dry the ribs. Then, remove the membrane from the back of the ribs. Simply loosen it at the edge with a butter knife, then pull to remove it from the ribs and discard it. (The membrane is a thin piece of shiny tissue covering the back of the ribs. Leaving the membrane intact will result in tough ribs.)
Season The Ribs With The Dry Rub. Mix the dry rub seasonings in a small bowl. Then season all sides of the ribs generously with the rub.
Pressure Cook The Baby Back Ribs. Add the water, apple cider vinegar, and liquid smoke to a 6-quart instant pot. Then, add the rack (trivet) and place the ribs lengthwise on top of the rack.
Close The Lid And Seal The Venting Knob. Set the manual pressure to high for 25 minutes for the baby back ribs. Let the pressure release naturally for 10 minutes, then release the vent to let out the remaining pressure. The pin drops when all the pressure is released. If you are making thicker ribs, like spare ribs, adjust the time to cook for longer: 35 minutes and allow the vent to naturally release. The pin drops when all the pressure is released. (Do not release the vent immediately as the natural release is necessary to tenderize when using thicker cuts of meat.)
Coat The Ribs With Barbecue Sauce And Broil. Carefully remove the ribs from the instant pot and place them on a baking sheet. Coat all sides of the ribs generously with barbecue sauce. Transfer the ribs into the oven and broil (on the highest setting) for five minutes, or until the bbq sauce is caramelized.
Serve. Serve with more barbecue sauce and your favorite sides. Enjoy!