What Is Marbling in Meat? Learn About the Different Types of Marbling and What Factors Impact Marbling

Marbling is the white flecks of intramuscular fat in meat, most notably red meat. The fat in lean muscle creates a marble pattern—hence the name. Marbling affects meat’s juiciness, tenderness, texture, and flavor—attributes that determine “eating experience.” In this case, more of all the above is better. Intramuscular fat should not be confused with intermuscular fat, which is the fat between the muscles. That fat, which you typically trim off, does not enhance a piece of meat.

• In the United States, Japan, and Australia, trained human graders visually appraise the amount of white fat flecks in muscle and their spatial distribution to determine the quality of meat.
• Graders evaluate the amount and distribution of marbling in the ribeye muscle after a butcher has ribbed the carcass between the 12th and 13th ribs. The degree of marbling is the primary determinant of quality grade.
• The USDA grading system features eight different grades—Prime, Choice, Select, Standard, Commercial, Utility, Cutter, and Canner, in descending order—and rewards marbling. Across almost every cut on beef carcasses, USDA Prime has the highest marbling content and costs the most on the market. Choice is accessible in a retail outlet like a grocery store. Select, while not quite as good as Choice, is a more affordable option, followed by Standard. A lower USDA grade typically winds up in ground beef products and in cheap steak restaurants.

Marbling comes in different shapes and sizes, and not all beef marbling indicates greatness. Although some people disagree about the quality of different types of marbling, the following is the generally accepted standard.

• Fine marbling. The lean muscle has a high frequency of thin, evenly distributed flecks of fat. These fine flecks melt during cooking, adding juiciness and tenderness throughout the meat. In the restaurant world, the most desirable types, like Kobe and Wagyu beef, have a high frequency and even distribution of fine marbling.
• Medium marbling. An inferior form of marbling, it features larger, less evenly distributed flecks of fat, which can negatively affect the cooking and eating experiences. Larger pieces of fat take longer to render and liquefy. As a result, when someone cooks a medium marbled steak rare or even medium rare, the fat will not render in time to add juiciness and tenderness to a steak. This leaves gelatinous flecks of fat that negatively affect mouthfeel. Uneven distribution can also lead to certain areas of a piece of meat being more tender and juicier while others are tough and dry.
• Coarse marbling. The least desirable type of marbling, it has large, uneven flecks of intramuscular fat. The problems with medium marbling are even more pronounced.

Marbling is a measure of quality, and as such the meat industry is always using meat science to make production more predictable and uniform, to boost profits. The following factors affect marbling in beef.

• Breed. Certain breeds have higher marbling scores on average due to the way they metabolize food. Cattle breeds such as Angus, Murray Grey, Herefords, Shorthorns, Japanese Wagyu, and Kobe are all high-quality breeds. Dairy breeds such as Jersey, Holstein-Friesian, and Braunvieh stand out as well. The breed can also affect the ratio of Omega-3 to Omega-6 fatty acids. For example, Wagyu, which is higher in Omega-3s, is a healthier breed of cattle.
• Feed. The type of feed and time that an animal feeds play an important role in marbling. If beef cattle aren’t gaining weight properly, marbling will disappear from their muscles quickly. Cattle that feed on grain often marble more easily than strictly grass-fed cattle, but not every feed is the same and, due to metabolism, not every breed is the same. The grass pellets used in industrial feedlots may lack the nutrients of grass on open pastures and rangelands.
• Muscle use. The same principles that apply to building lean muscle and burning fat at the gym apply to animals and marbling. Less heavily worked muscles, like the loin, have more fat and thus produce the most marbled cuts. Active leg, shoulder, and rump muscles result in leaner, less marbled cuts.
• Age. The age of cattle is important. When an animal is too young it won’t display marbling. Veal, or young cattle, develop intramuscular fat last, after subcutaneous fat, kidney, pelvic, and heart fat, and intermuscular fat. Older animals aren’t ideal, either.
• Cut. The particular cut of meat also plays a role. Some beef cuts, like a Tenderloin Steak, have less marbling but, due to the fine structure of their muscle fiber, are tender even though the cuts of meat aren’t incredibly juicy or flavorful. Prime NY strip has a high concentration of marbling, but, unlike tenderloin and ribeye, its large muscle fibers can overpower the fat.

Marbling in uncooked meat looks aesthetically interesting, but that is not why it’s special. The presence and type of marbling in meat is important for several reasons.

• When cooking, marbling adds flavor and juiciness as the fat melts into the steak. The marbling keeps the meat moist, so natural juices don’t evaporate in the pan.
• Fat is far more tender than muscle fiber in steak. As a result, marbling adds tenderness, which is a preferable mouthfeel.
• Some fats are undeniably bad for you, but the intramuscular fat that creates marbling can be good for you. Breeds like Wagyu are higher in healthier fats like oleic acid, which can reduce the risk of coronary heart disease.

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