Knackwurst (also spelled knockwurst) is a short, plump, smoked German sausage of finely ground beef and pork seasoned with garlic and packed into a taut natural casing. Cured and lightly smoked, it is sold ready to heat — simmered, steamed or grilled until it gives the loud "knack" (snap) of its bursting skin that gives the sausage its name.