Under the Chicago method of cutting, the loin represents about 17 per cent’ of the weight of the side, but there are variations depending on the type and grade of the carcass. It contains the choicest, most valuable, and most preferred retail cuts of the entire carcass. Preference for loin cuts is due to their relative tenderness and quality. The groups of muscles in the loin and in the rib are relatively thick. They are the least used in the movements of the animal, and are well protected by bone and fat. The tenderloin or fillet is a part of this cut.
The loin is subdivided into the “loin end,” which is the thick portion next the rump, and the “short loin” or portion next to the ribs. The retail cuts derived from the loin end are sirloin steak and sirloin roasts. From the end of the short loin next to the loin end porterhouse or T-bone steaks are taken. These are sometimes called tenderloin steaks because they contain a part of the tenderloin. This tenderloin, however, is comparatively short, and when it runs out the remaining portion is cut into club or Delmonico steaks.
The grade of the loin corresponds with that of the side from which it is taken, and is determined by quality, conformation, and finish. Evidences of these characteristics are depth of flesh, amount and color of surrounding fat, marbling, and firmness and color of the flesh.
No. A 1, or Prime, Beef Loin
No. A 1, or Prime, beef loins are derived from A 1, or Prime, steer and heifer carcasses. Naturally, supplies of this grade are small. A steer loin of this grade is well rounded, convex, or bulging from end to end, and is well covered with fat. A heifer loin is slightly less convex, but is well rounded. Loins of this grade are smooth, have excellent depth of flesh in proportion to length and weight, which gives them a relatively short, compact, and heavy appearance. The flesh is well marbled with deposits of flaky-white fat, is fine-grained, firm, tender, and of light or cherry-red color. The fat covering is abundant and evenly distributed over the outer surfaces, but does not average more than three-fourths inch in depth over the top of the loin. It is firm to the touch and of creamy or clear white color. The kidney fats are not excessively wasty, and are white, crumbly, and of best quality. Such loins are sold chiefly to high-class hotel and restaurant trade.
No. 1, or Choice, Beef Loins
No. 1, or Choice, beef loins are derived from No. 1, or Choice, steer, heifer, and cow carcasses. In shape they do not differ materially from prime loins of the respective classes, being always smooth, well developed, and very compact. Such a loin may differ from a No. A 1, or Prime, loin in finish, which is apparent in the depth and amount of fat covering and in the amount of suet. Generally, the fat covering and suet are thicker and more wasty, but not excessively so. A Choice loin may have the superior conformation and finish of a prime loin, but may show deficiencies in quality which may be indicated by hardness of bone, coarseness of grain, or by a slightly darker color of flesh. Choice loins are far above the average, and are sold chiefly to hotels, restaurants, and retail meat dealers catering to a discriminating trade.
No. 2, or Good, Beef Loins
No. 2, or Good, beef loins are from good grade steer, heifer, and cow carcasses. The sex characteristics are more pronounced in this than in the higher grades. Good loins from all classes have depth of flesh above the average but are deficient in this respect as compared with Choice and Prime loins. Good steer and heifer loins are moderately well rounded, but appear proportionately longer than Choice or Prime loins of the same classes. A Good cow loin is almost flat, but is fairly well fleshed. The heavy end appears unusually large when compared with the small or rib end. Loins of this grade are well covered with fat varying in thickness from one-half inch to slightly more than an inch. It often is rough, and may be slightly gobby. Cow loins of this grade are noted especially for their wasty fat covering. All Good loins have some marbling. This is the lowest grade in which marbling is found. The flesh is firm and of smooth grain, and varies in color from light to cherry-red. The color of the fat varies from a creamy to slightly yellowish color, but is of a quality which indicates that the finishing process included grain or other good ration. Loins of this grade are in evidence throughout the year in retail meat shops catering’ to a trade requiring meats above the average quality.
No. 3, or Medium, Beef Loins
No. 3, or Medium, beef loins are from No. 3, or Medium, grade steer, heifer, and cow carcasses. They have only an average depth of flesh and fat, are angular, and lack the compactness of the better grades, and are relatively longer and flatter. Some steer and heifer loins of this grade have much of the convex appearance of the Good grade, but most of them are flat or slightly “dished” or concave in the “short loin.” The broad ligament along the side of the backbone often is visible. All Medium cow loins are flat or concave and very angular. The fat covering of loins of this grade is thin and inclined to bunchiness, especially over the thick part of the loin and particularly in cow loins. The color of the external fat, the suet, and intermuscular fat is white or slightly yellowish and of average quality. The flesh generally is coarse-grained, watery, inclined to be tough, and has a slightly dark red color.
The muscles of a Medium grade loin, and those of the lower grades, often slip from their natural positions, even after having been thoroughly chilled. Flesh produced by grass alone rarely remains set in the cuts, even when chilled. Loins of this grade are on the market throughout the year.
No. 4, or Common, Beef Loins
No. 4, or Common, beef loins are derived from No. 4, or Common, steer, heifer, and cow carcasses. They are flat, relatively long, very angular, rough and have little or no covering or deposits of fat in the muscle seams or over the tenderloin. The limited amounts of fat which may be present are soft and have a yellowish tinge. There is a relatively greater proportion of bone to flesh and fat in this grade than in any of the higher grades. The broad ligament along the side of the backbone is plainly visible. The flesh is watery, tough, stringy, and dark red, and rarely remains set in its natural position. Loins of this grade are marketed throughout the year.
No. 5, or Cutter, Beef Loins
No. 5, or Cutter, beef loins are chiefly from No. 5, or Cutter, cow carcasses, and a relatively small percentage is from No. 5, or Cutter, steer carcasses. They are very thin, flat, or concave, long and angular, have little or no fat covering, and have scarcely any suet or intermuscular fat. The flesh is dark, coarse, stringy, tough, and watery. Very few steers, and practically no heifers, contribute to this grade. Such loins are sold to restaurants and dealers that cater to a trade requiring low-priced meats.