What you see in the grocery store labeled as "ground beef" is seriously "mystery meat", which can include trimmings from anywhere on the animal. Unfortunately because it is often hastily trimmed, and considered a pure profit product, it can include tiny bits of hard cartilage and bone. And bloody veiny things. Yuck. Ground meats labeled "ground chuck" or "ground sirloin" are at least a step above in letting you know where the trimmings came from. The exception is ground round, which is too lean, tends to be livery in flavor, and cooks up firm and flavorless. Then there are the best ground beef categories, which specify combinations of cuts coming from the short ribs, brisket, flap meat, flank, skirt, and are often combined with the chuck for 20-25% fat. Pure brisket ground into burgers would be pretty great. Grinding your own meat is a great way to get much higher quality at a lower price. Ground beef mystery meat is overpriced in my opinion.
