Threshing, also spelled thrashing, is the process used to separate the chaff, the protective covering around the grain, and the kernel of grain we use for food, from a plant’s stalk. During the nineteenth century, farmers used a variety of methods to remove the chaff and grain from the stalk and to crack open the chaff. Some used flails, others used hand-powered machines such as this, and still others used animal-powered machines. Today, farmers thresh primarily with gasoline-powered machines.