How to Trim Spare Ribs: Step By Step Guide for St. Louis Style
So you want to cook St. Louis-style ribs but your butcher only had spare ribs?
No need to panic, you can trim a full rack of spare ribs into St. Louis cut ribs with just two simple cuts.
You’ll also save a bit of cash by learning how to process the ribs yourself.
What is St. Louis cut?
Before we get into the “how,” let’s talk about the “why.”
When you’re shopping for pork ribs, you’ll see a number of different options to choose from.
Pork ribs are separated into two sections: the spare ribs and the loin-back ribs (often called “baby back ribs”).
You will also see a popular cut called St. Louis cut spare ribs.
The reason the St. Louis style cut of pork spare ribs is so popular is that it removes a section of the spare ribs that contains a lot of cartilage and tough-to-eat portions.
It leaves you with a cleaner, more uniform rack of ribs that will be easier to eat and look better presentation-wise.
Tools you’ll need
The most important tool to have when you are trimming ribs is a sharp boning knife.
I recommend the Smoke Kitchen 6.5” Boning Knife. Whether you are trimming a single brisket or you need to prep 20 racks of ribs, you’ll appreciate how nicely this knife fits in your hand.
It’s made from a combination of carbon and chromium and will stay razor-sharp to give you even cuts with minimal effort.
Trim the fat cap off a brisket or square up a rack of ribs in seconds.
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The other thing you want to have is a sturdy surface to work on.
A butcher block is a great choice for trimming ribs, but I like to use my BBQ Drip EZ Prep Tub. It is a durable prep tub that has a built-in cutting board plus a lid for storing your meat in the fridge once it is prepped.
How to trim a St. Louis cut
As I mentioned, it only takes two simple cuts to turn a full rack of spare ribs into a St. Louis cut rack.
The process takes about 5 minutes (or less once you get the hang of it).
1. Remove the end flap
At the smaller end of your rack of ribs where the shortest bone is located, there will be a small flap of meat that is rounded at the edge.
This flap of meat won’t cook evenly with the rest of the rack of ribs, so it’s best to just trim it off.
2. Remove the breastbone
Find the place where the longest rib bone ends.
You will be able to feel a softer portion of cartilage that runs down the entire length of the rack of ribs separating the breastbone from the spare ribs.
Using your boning knife, start at the side of the rack with the long bones and trim in a straight line to remove the breastbone.
Once it’s removed, your rack should resemble a rectangular shape and you now have what is called a St. Louis cut of spare ribs.
3. Trimming your ribs
Now you’re technically done trimming your spare ribs into a St. Louis cut, but I like to do a bit more trimming before I’m ready to season and smoke my ribs.
Flip the ribs over so that the bone side is facing upward.
There may be a skirt attached to the upper portion of the ribs. Some butchers will have already removed this flap, but I find that the majority of racks that I buy still have it attached.
Again, this is a portion of the rack that won’t cook evenly during the smoking process, so it’s best to remove it.
Finally, locate the membrane on the back side of the ribs. The membrane doesn’t have to be removed, but it can create a tougher bite in your final product so I like to remove it.
To remove the membrane, simply run your finger under the membrane in the very center of the rack.
Wiggle your finger up until the membrane is removed in that section, then pull upward firmly to remove the membrane from the entire rack.
If you have trouble gripping it, grab a paper towel to give you a little extra grip.
If you need more guidance on removing the membrane, check out our article on How to Remove the Membrane from Pork Ribs.
What to do with the scraps
Nobody likes wasting meat that they paid for, so don’t throw your scraps away! There are plenty of ways to utilize the meat you’ve trimmed off your spareribs.
You can save the flap meat for making sausage and burgers, but the most essential part to save is the breastbone section.
It is the first portion that you cut off, and it is the perfect trim to make rib tips with.
You can season and smoke that section alongside your St. Louis cut ribs, and they will cook faster than the rest of the rack, so it makes a good snack to munch on while you wait for the rest of your ribs to finish smoking.
Recipes for St. Louis Cut ribs
Now that you’ve trimmed your rack, you’re ready to season them up and get them on the smoker!
Here are some great recipes you can use to smoke the perfect rack of ribs: