The next step is making a horizontal cut to severe the breastbone and cartilage. To find the sweet spot for this cut, first locate the longest rib, usually the fourth bone in on the wider end of the rack. Feel along that rib until you detect a softer spot: That’s a cartilaginous section where the rib connects to the sternum (breastbone). All the other ribs connect to the breastbone in the same way. Make the cut by inserting the knife into the soft spot, then slicing perpendicular to the ribs, cutting through all of the soft spots where each rib meets the breastbone. Once the breastbone is removed, you should have a clean, rectangular rack of ribs with nothing but bone and meat, perfect for easy eating.
As for the scraps of meat I trimmed, I try not to throw them away. I tend to freeze the flap meat for sausage-making. Even more worth saving, though, is the breastbone portion: It’s the part that rib tips come from, which is Chicago barbecue’s claim to fame. I like to season and smoke this piece along with my St. Louis-cut ribs. The tips are done sooner than the full rack, so I take them off the grill sooner and have them as a cook’s treat while I wait another couple hours for the ribs to finish. Sure, they’re a bit of a pain to eat, but those fatty tips are also damn delicious.
From start to finish, the entire trimming process only takes a few minutes, and after a rub and 5 to 6 hours in the smoker, you’re left with nothing but serious eats.
