There is a “rubbery” membrane on the backside of pork ribs. Competitive Pitmasters will always remove this membrane prior to cooking. Leaving the membrane intact will make a well cooked rack of ribs mediocre. The membrane adds nothing to taste and tenderness and only distracts from it. Also removing the membrane allows seasoning to come in direct contact with the meat.
To remove the membrane can be frustrating. Place the ribs on the counter meat side down. Slide a knife under the very end of the membrane at the widest part of the rib. It’s only necessary to pick up an edge of the membrane enough to grab with your thumb and forefinger. With a paper towel grab hold of the membrane and tear back to the narrow end of the rack. Many times only a portion of the membrane will pull off so you have to start the process over to remove the remainder.
Sounds like a lot of work but if you want your guests to have a first class BBQ experience it is well worth it.