marbling

Marbling is the intramuscular fat dispersed within skeletal muscle. It appears as thin white streaks or flecks interspersed with lean tissue and is distinct from subcutaneous fat under the skin or intermuscular fat between muscles.

The marbling pattern is influenced by genetics, diet, age, and management. Adipocytes within the muscle store fat (intramuscular fat) that increases with energy-dense, grain-based diets used in finishing cattle. Some breeds, particularly Wagyu and other Japanese cattle, tend to develop higher marbling. Marbling generally increases with maturity, though excessive fat is not always desired for other considerations.

Measurement and grading: In beef, marbling contributes to overall grade and palatability. In the United States, beef grades such as Prime, Choice, and Select reflect marbling and fat cover, with Prime representing the highest level. In Japan, Wagyu beef is scored on a marbling scale (Beef Marbling Score, BMS) where higher scores indicate more intramuscular fat. Modern methods may use imaging or other technologies to estimate intramuscular fat.

Culinary relevance: Higher marbling typically enhances flavor, juiciness, and tenderness because the fat melts during cooking and helps baste the meat. Marbling influences suitability for different cooking methods; highly marbled cuts are prized for fast, high-heat cooking as well as slow roasting, while leaner cuts may require careful preparation to maintain moisture.

Variability across species: Marbling also occurs in pork and lamb, though its extent and sensory impact vary. In all meats, marbling is one determinant of texture and eating quality, balanced against overall fat content and dietary considerations.