Naturally, the toughest parts of beef are found around the legs: The shanks, the rounds, the shoulders, the brisket, and the neck. Round or Heel of Round is another incredibly tough cut of beef, which is why it usually gets made into ground beef with a sampling of other tougher muscle cuts and trimmings.
While fat and marbling are most known for taste and flavoring, there is a correlation to the toughness of the meat, thanks to the microscopic fat cells found in the muscle fibers. Without these microscopic fat cells, beef will be tough and lacking flavor.
But beyond structural support, cattle’s size means that parts otherwise considered soft tissue can prove hardier than expected.
“Beef tongue has become a trendy item on restaurant menus, but it’s long been a staple in traditional Mexican cuisine,” says Russell Woodward, Beef Product Specialist at the Texas Beef Council. “It's used daily in the harvesting of the grasses they eat, making it tough. It has a unique flavor like other organ meats do. It can be used in a variety of ways, sliced thin, like charcuterie.”