How to Trim Spare Ribs to a St. Louis Cut (with Pictures!)

By Dylan Clay
Last Updated 
November 3, 2022

While it's entirely possible to smoke a full rack of pork spare ribs - not many people outside of barbecue enjoy eating rib tips. They're filled with cartilage, which can be off-putting for some people.

Spare ribs are traditionally trimmed to a St. Louis Cut - this involves removing the rib tips, the flap meat, the membrane, as well as smaller bones.

There are also other parts like the false-lean that people fail to mention - which I think should be removed.

What are Spare Ribs?

pork spare ribs packaged

Spare ribs are taken from the bottom of the ribs, or the underbelly of the pig. They extend around the belly and connect to the sternum.

pork ribs location

When compared to baby back ribs, Spares are more meaty, less tender, and tend to be more flavorful due to the fat content.

Depending on how they're butchered, a full rack of spare ribs usually contains 13-15 rib bones and will be roughly 1/4" thick.

What is a St. Louis Cut?

A St. Louis cut refers to a style of trimming for spare ribs.

st louis trim cuts made

In the mid 20th century, small meat packing plants in St. Louis decided to remove the sternum bone, cartilage, and rib tip. The resulting rack was more uniform and rectangular-shaped.

st louis spare ribs trimmed

The namesake for this style of trimming stuck and people now call these "St. Louis cut" ribs.

Essentially, the St. Louis cut removes the rib tip, flap meat, and small bones. The result are what's called "center cut" spare ribs.

st louis cuts parts labeled

This style of trimming is even recognized by the USDA and Agricultural Marketing Service (AMS). They list this cut as #416A - Spareribs, St. Louis Style - and even have specifications for how it's cut.

How to Trim Spare Ribs to a St. Louis Cut

In order to trim pork Spare ribs to a St. Louis cut, all you'll need is:

  • Plastic cutting board
  • Sharp knife
  • Butter knife
  • Spoon
  • Paper towels

1. Remove from Packaging and Pat Dry the Ribs

The first thing to do is remove the ribs from their packaging.

pork spare ribs pat dried
Pork spare ribs pat dried, bone-side up

Start by using your knife to cut open the vacuum seal packaging. Pull the spare ribs out and throw the vacuum seal material in the trash.

Place the ribs on your plastic cutting board or disposable work surface.

Use paper towel to pat dry both sides of the spare ribs - the meat side and the bone side. The reason for doing this is that it makes it easier to work with the meat.

2. Remove the Flap

Have the spare ribs oriented so that the bone side is up.

spare rib flap meat location

With your sharp knife, remove the "flap" meat; The flap meat is the diaphragm of the hog.

Removing the flap is as simple as gliding your knife underneath it. You want to remove this piece so that the bone-side is flush.

cutting rib flap meat

This piece has a tendency to burn when left on and will cook unevenly from the rest of the rack. However, it's wonderful meat - it's essentially the equivalent of skirt steak on a steer.

3. Remove the Rib Tip

The rib tip faces the underside of the hog and connects to the sternum.

The rib tip doesn't contain any bones (unless the breast bone is left attached, like mine) and while it's a decent portion of meat, it's also filled with cartilage. For this reason, most folks don't enjoy eating them.

The first thing I do is rotate the ribs so that the large bones are facing me. On every rack of spare ribs there will be an end with small bones and an end with large bones.

I then count 4 ribs from the large bone side and make a parallel cut.

4th rib bone

Note: The small bone found to the right of the 1st rib bone is removed in the next step. This small bone on the large bone side isn't always present.

The reason for starting at this rib bone is that the first 4 ribs typically have tough cartilage to get through.

Starting at the 4th rib makes it easier to cut as it's more visible in terms of where the bone starts and ends.

Once you make that initial cut you want to continue in a parallel line, cutting all the way through the cartilage in order to remove the rib tip.

rib tip cut
Rib tip (pictured right) separated from pork spare ribs

4. Remove Smaller Bones

On every rack of spare ribs there is one side with large bones (as detailed above), and a side with smaller bones.

Personally, I like to remove smaller bones so that my Guests get similar sized bones on their plate.

From the large bone side, count 10 to 11 bones. At the 10th or 11th bone, slice close to the small bone you're removing so that the 10th or 11th bone on the rack has more meat on it's adjacent side.

count 10 to 11 rib bones and slice

On this rack, on the large bone side there was a sharp piece of bone left in the rack. I removed this bone before counting.

small bone on large bone side

To note: For this article specifically, my rib rack had 15 bones. I opted to count 11 bones and slice at the 12th because of the size of the ribs.

5. Remove the False Lean

Flip the rack over to the meat side to remove the false lean. The false lean is the insertion point of the pectoralis muscle.

false lean

Essentially it's a small layer of lean meat on top of silverskin and it's less enjoyable to eat in comparison to the rest of the lean meat.

Not many people go over this part much but I think it's worth removing. If I'm being lazy, I'll leave it on, it's entirely personal preference.

In order to remove it, use your knife to initially cut into the seam/silverskin. You'll start to notice that as you glide your knife underneath, the false lean will want to naturally pull away.

removing false lean

Note: Some people like to remove this part first but in my opinion, it's easier done when the rib tip is removed - which contains the sternum/breast bone and most of the muscle itself.

Here's the false lean removed:

false lean removed

That surface fat remaining on the ribs isn't hard fat and will render without an issue.

Silverskin separates and support muscles, allowing them to slide past each other easier; It's essentially Spanx for skeletal muscle. With that said, it's also protein elastin and will not render and leaves a rather chewy mouthfeel.

Which is why I'd suggest removing it. For that same reason, you remove the membrane from the bone-side of the ribs.

6. Remove the Membrane

Flip the rack to the bone side.

st louis spare ribs membrane removed
Use my secret tool, a spoon!

The membrane on ribs is removed because it improves the eating experience. Again, the membrane is a thin layer of protein elastin and won't render when smoked.

Put simply, the membrane results in a chewy mouthfeel that most people find unpleasant.

I have a more detailed article on removing the membrane from ribs, found here.

However to condense it:

  1. Initially lift the outer membrane with a butter knife so that you can fit the back-side of a spoon underneath it. Use the spoon to further lift the membrane so that you can remove it cleanly.
  2. When lifted from end to end, use a paper towel to grip and pull the membrane horizontally off the rack of ribs.
  3. Discard the membrane in the trash.

It should be noted that there are two membranes on the back of ribs. Your goal is to remove the outer silverskin.

Removing the inner membrane would cause the rack to fall apart when smoked.

Wrapping Things Up

After the above trimming process you're left with St. Louis cut ribs. From there you can apply your seasoning/dry rub and then throw them on your smoker.

While the above is a fairly straightforward process, if you deem the above wasteful, I'd recommend looking for pre-trimmed St. Louis cut ribs or simply smoke the spare ribs whole.

Both options are readily available in most grocery stores.

Dylan Clay
I've grilled and smoked meat for roughly half my life. While i'm not a professional Pitmaster, I've worked with nearly every cut of meat. Not everyone has a hands on guide to teach them BBQ. It's my hope that Barbecue FAQ can be that helping hand.

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