Cindy Kinder the Extension Educator for Gooding County was my teacher.
To grade my beef we measured the size of the rib eye, back fat, and figure the kph fat, and you must have the carcass weight.
These two beef graded prime minus and choice plus.
Grades are based on the amount of marbling in the meat and the age of the animal. Marbling is the flecks and streaks of white fat you find distributed throughout the meat. In general, the higher the degree of marbling, the more tender, juicy, and flavorable the meat will be. Higher grade meats come at a higher cost.
Beef is best in flavor and texture when cattle are between 18 and 24 months old, so the grading favors younger animals.
Meat graders assign a yield grade to a carcass by evaluating:
- the amount of external fat;
- the hot carcass weight;
- the amount of kidney, pelvic, and heart fat; and
- the area of the ribeye muscle.
There are eight distinct grades of beef recognized by the USDA.
USDA Prime Beef
- is the ultimate in tenderness, juiciness, and flavor.
USDA Choice Beef
Choice grade beef has less marbling than Prime, but is still of very high quality. This is the most popular grade of beef because it contains sufficient marbling for taste.Just over half of the beef graded each year earns a grade of Choice.
USDA Select beef
This is generally a lower priced grade of beef with less marbling than Choice. Select cuts of beef may vary in tenderness and juiciness.USDA. In order of descending quality they are:
- Prime
- Choice
- Select
- Standard
- Commercial
- Utility
- Cutter
- Canner
I got all my information from
http://meat.tamu.edu/beefgrading.html
http://www.bbqreport.com/archives/barbecue/2006/03/02/understanding-the-usda-beef-grading-system/
for more information click the links above.