Meat science: Top sirloin research reveals opportunities

MeatsPad is the official podcast of the American Meat Science Association, a platform dedicated to sharing breakthrough knowledge in a way that is accessible to the meat industry.

Podcast Host Phil Bass, a professor of meat science at the University of Idaho (UID), interviewed Sierra Jepsen, owner and lead butcher of Butcher Solutions, LLC, during an episode dated April 11.

During the podcast, Bass and Jepsen’s topic of conversation focused on Jepsen’s research project at UID on the top sirloin, a sub-primal cut of the beef loin primal. 

In 2022, Jepsen received her master’s degree from UID, focusing on meat science with an interest in innovative carcass fabrication and was an assistant lecturer at the University of Wyoming (UW) from 2017-21, where she coached the UW Meat Judging Team and managed the Cowboy Branded Meats program. 

Jepsen’s project aims to identify other grillable items which can be created from the top sirloin. 

After graduation, Jepsen opened Butcher Solutions, LLC in Livingston, Mont. and specializes as a traveling butcher school and meat industry consultancy focused on hands-on meat science education.

A guide to cuts of beef

While shopping for beef cuts, many have probably wondered where the best cuts of beef come from, which piece is most tender or which is best to grill. 

Meat is separated from the animal carcass in a primal cut – the first cut made in the butchering process. A beef carcass is initially divided into eight primal cuts.

According to the U.S. Department of Agriculture (USDA), primal cuts are then divided into hundreds of sub-primal cuts, not to be confused with Prime cuts, which refer to a high-quality finished cut of beef.

Each cut’s flavor, tenderness and price are determined by the characteristics of the primal cut they originate from. Usually, the further away a muscle is from the horns and hooves, the more tender and pricier it is.

The loin primal contains the short loin and the sirloin, located behind the ribs at the top part of the cow, furthest away from the horns and hooves.

The USDA website shows sub-primal cuts from the loin primal are the tenderloin, strip loin, short loin and sirloin, and these cuts are highly regarded as some of the most tender on the entire animal. But, the top sirloin has been viewed as one of the lesser-value cuts.

Top sirloin is the transition from back to the rump of the animal and is viewed as less desirable, but recent research at UID has brought this sub-primal cut into the light of consumers. 

Top sirloin

research project

Jepsen conducted her thesis on profiling the muscles of the beef top sirloin and has discovered evidence the top sirloin should receive more attention.

“There are four muscles in the top sirloin sub-primal cut – biceps femoris, gluteus medius, gluteus accessorius and gluteus profundus, and by separating the muscles individually before cutting steaks, the top sirloin muscles can then be better managed and merchandised,” Jepsen states. 

She notes even if the top sirloin is selling well, the industry can dive deeper into dividing the four muscles up and bring more value to the sub-primal cut. 

“The biceps femoris, also known as the top sirloin cap, is great as a grilling roast, while the gluteus medius, known as the top sirloin center cut, is less popular than the top sirloin cap due to the cap actually being more tender,” she says.

However, Jepsen and Bass agree the center cut should not be overlooked. Jepsen describes how to identify the seam of connective tissue running through the center-cut top sirloin, cut down this seam and effectively remove the “chewy stuff” from the equation. 

“Performing this butchering technique turns the gluteus medius muscle into two very consistent roasts which can be prepared in this manner or cut into steaks resembling tenderloin filets known as ‘baseball top sirloin steaks,’” she adds.

Although top sirloin center-cut steaks are not as tender as the tenderloin, they are still considered “very tender” by USDA standards based on Jepsen’s research.

Jepsen notes, “The remaining muscles in the top sirloin are much smaller than previous cuts, and when combined, they make what is called the ‘mouse’ of the top sirloin. When separated, one of these two muscles turns out to be a ready-to-grill steak that is also the most tender in the whole top sirloin.” 

Jepsen’s research discovered the gluteus accessorius is about eight to 10 ounces naturally, which means it’s practically already portioned when it comes off of the carcass, and being so tender, it lends itself to the user-friendliness of the grill.

Before Jepsen’s research, the top sirloin was made into ground beef, and because of this study, the only thing remaining on the top sirloin for ground beef now is the last muscle – the gluteus profundus.

Melissa Anderson is the editor of the Wyoming Livestock Roundup. Send comments on this article to roundup@wylr.net.