Ham hock is the smoked pork product traditionally used to flavor collard greens. The hock is the joint at the lower end of a pig’s leg, near—but not including—the foot, and it contains skin, connective tissue, and a small amount of meat.
Because ham hocks are tough, they are simmered slowly with the greens. Long cooking releases pork fat, gelatin, salt, and smoky flavor into the pot, producing the savory broth often called pot liquor. The greens absorb that seasoned cooking liquid as they soften.
Ham hocks are a foundational ingredient in soul food and Southern country cooking. They are also used with mustard greens, cabbage, green beans, navy beans, and pinto beans. Their usefulness reflects an older tradition of making rich meals from inexpensive cuts rather than wasting them.
Bacon is also used in some collard-green recipes, and vegetarian versions may rely on smoked salt or liquid smoke. However, ham hock is the classic whole-pork cut traditionally associated with seasoning a pot of Southern collard greens.