The Loin Primal

Tenderloins, short loins, sirloins… Sirloin caps, sirloin tips, strip loins… top sirloins, bottom sirloins… what’s the deal? If the word “loin” shows up on a label, should a shopper have reason to believe the cuts are related to each other? Will they taste alike?

Today we’ll break down the loin primal. The “primal cuts” refer to the four sections into which a steer carcass is separated with the butcher’s very first cuts, to set the stage for further processing. Each of these sections can weigh north of 100 pounds, and from the front of the animal to the back, they include the chuck (shoulder), rib, loin, and round. The loin, ranging from the bottom of the ribs to the pelvic region of the animal, contains some of the best known cuts, with some “not-like-the-other” treats thrown in to keep us on our toes and help our understanding of the muscular organization of the animal as a whole.

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A life spent relaxing

The defining cuts of the loin are known for tenderness; that is, the lack of connective tissue which results from stress put on the muscle during the life of the animal. When muscles strain and tear during hard work, the body compensates by producing tough, stringy tissue that acts as a support system for the animal. The brisket, or pectoral muscle, is the prime example of a muscle utterly saturated with connective tissue after a life of bearing the weight of the entire front side of the animal. These muscles require low, slow cooking to render the proteins of the connective tissue into edible form.

Meanwhile, the loin is situated such that its muscles do relatively little work to support the standing steer. This means little connective tissue: extremely tender but without the beefy flavor of the hard-working muscles.


Mildly coarse muscle fibers in the bavette.


Short Loin and Drop

As with the neighboring rib section, the loin is divided into two main camps, the short loin and the drop. If you put your hands on your hips, your thumbs are pressed up against your “short loin,” the group of muscles that provide support to the backbone (yours probably won’t be quite as tender, as they have to keep your body upright). With your hands still on your hips, your fingers wrap down to your “drop,” where the muscles are a little less organized but you’ll find beefier muscle fibers that make for some of the best economy cuts.

Drop

Because it’s less involved, let’s get the drop out of the way. The belly section of the steer is a mess of membranes, fibers, and fat that forms the bottom of the bag necessary for holding the animals organs (remember, that’s four stomachs). After working through membranes, you’ll find the long, flat muscles that would traditionally sell for less than their “genuine steak” buddies from the short loin. These delicious muscles from the drop are the flank and the sirloin flap (bavette).


Flank steak grilled to medium rat


Short Loin

Now for the previously mentioned “genuine steak” favorites from the short loin. The most famous of all is the tenderloin (psoas major), which is cut into medallion steaks to create filet mignon. This muscle runs the length of the spine, and with little work to do, is the most tender muscle on the animal (it carries a neighbor muscle, the psoas minor).

Shop filet mignon.


Raw filet mignon, the tenderest cut on the animal.

Strip Loin With your hands once again on your hips, you might correctly figure that the bones and muscles that run along the spine will be better organized than the large group of muscles required to operate closer to the pelvis. This vertebrae-supported section is the strip loin, becomes New York strips when cut against the length of the muscles (the bone-in New York strip contains a little touch of the spine). For a porterhouse or T-bone steak (almost identical but with some adjustments), the tenderloin would not have been removed earlier, essentially creating a New York strip with the filet mignon still attached on the other side of the bone (look up a picture of a T-bone, you’ll see).

Shop steaks from the short loin.


New York strip steak. Read more here.

Who’s left? Sirloin

Now that we’ve removed the well-organized steaks, it’s time to dive into the sirloin, the huge mass of muscle that maintains the pelvic region of the animal. This section includes the ball tip, a piece of the sirloin tip that is otherwise located in the round section, as well as the  tri-tip, well-known as a barbecue favorite in California and Texas. Finally, we have a large muscle known as the top sirloin, which is commonly cut into steaks for a slightly more elegant alternative to the common sirloin steak.