What Is Beef Marbling?

Marbling in beef refers to the visible white streaks of intramuscular fat that run throughout the muscle tissue in any particular cut. Highly marbled steaks and others cuts of beef are highly sought after, as the intramuscular fat liquifies during the cooking process and provides a kind of self-marinating effect. As the marbling melts, it infuses the beef with a savory richness and velvety texture. Each bite of a well-marbled steak delivers extraordinary juiciness and robust flavor beyond compare.

Certain breeds of cattle naturally produce more intensely marbled beef, such as Japanese wagyu.

Intermuscular vs Intramuscular Fat

Let’s talk about fat. There are two kinds of fat in cattle: intermuscular and intramuscular.

  • Intermuscular fat refers to those solid white chunks or strips of fat between the muscles. This is the fat you or your butcher trim off before cooking or eating because it doesn’t contribute to an elevated dining experience. If you’ve ever tried to eat cooked intermuscular fat, you understand why it’s the origin of the phrase “chew the fat.” It’s rubbery and, other than the charred exterior, can be unpleasant to eat.

  • Intramuscular fat, on the other hand, occurs inside the muscle tissue. It’s those flecks and streaks of white you see scattered among the red parts of the meat. When we say marbling, this is what we’re talking about. The name comes from its resemblance to swirled color patterns on marble and other kinds of stone. We’ll get to more on how it affects flavor in a moment.


The Japanese use an international grading system called BMS, or Beef Marbling Score. This system assigns a number between 1 and 12 to reflect a cut of meat’s overall level of intramuscular fat. Beef Marble Score helps compare beef across international grading scales that may differ from USDA guidelines and cause confusion.

USDA Prime grade maxes out at a BMS of 5, whereas luxurious Japanese Wagyu beef can score as high as 12.

SRF Beef Grading

↑ Marbling score chart depicting the different levels of intramuscular fat.


What makes Japanese cattle (wagyu) special is that these breeds naturally produce higher densities of intramuscular fat marbling, creating much richer flavor compared to regular beef. Some specific breeds of wagyu, such as Kobe, are famously known to be fed and raised in a manner to further encourage even more fat marbling as the cattle grows from a young age.

The fat marbling seen in cuts of wagyu steaks ultimately comes down to genetics, and the ability of a skilled and experienced rancher who can safeguard the lineage and properly care for the cattle during raising. Diet and stress levels of the animals, as well as other cattle rearing practices, can all play a part in the resulting marble score.


The fat content of wagyu beef is primarily made up of monounsaturated fat, which is considered a healthy type of fat rich in vitamins and beneficial fatty acids, and does not contribute to an increase in cholesterol. This is different from unhealthy types of fat, such as trans fats found in fried foods or margarine. 

While wagyu fat is perfectly healthy, some do find it difficult to finish a cut of wagyu steak if served in a typical Western sized portion (i.e. 6 oz). The very high levels of fat marbling seen in wagyu beef creates a richness that leaves some too full to finish the entire meal. This is why Japanese wagyu is often served in thinly sliced, smaller portions.

One solution to this issue is American Wagyu beef, a cross between Japanese wagyu and North American cattle. The result is the best of both worlds, experiencing the richness of wagyu marbling while being able to fully enjoy the classic preparation of a cowboy ribeye, filet mignon, or even a low and slow cooked brisket.


All Snake River Farms American Wagyu beef grades above USDA Prime. One of the marvelous qualities of Wagyu cattle is that they naturally produce more marbling than other breeds. Part of that marbling comes from the carefully controlled diet we feed our cattle, including local grass and other grains. But part of it is simply a genetic trait — which is why our founder gambled on importing Japanese Wagyu in the 1980s and crossbreeding them with domestic cattle.

Because our American Wagyu beef surpasses most other domestic beef in marbling, we developed four categories for our products by synthesizing the USDA and Japanese systems:

  • USDA Choice – BMS of 2 to 3, great flavor and tenderness, above average steaks
  • USDA Prime – BMS of 4 to 5, includes only about 5% of all domestic beef
  • SRF Black Label™ – American Wagyu beef with a BMS of 6 to 8, superior to USDA Prime
  • SRF Gold Label™ – American Wagyu beef with a BMS of 9+ that delivers a rich flavor and buttery texture