Pumpernickel grain is a type of RYE, which is a cereal grain that has been cultivated for centuries. It is a dark, dense, and slightly sour-tasting grain that is used to make breads, cakes, and other baked goods. It is also used in some alcoholic beverages. Pumpernickel grain is high in fiber and contains many essential vitamins and minerals. It is a popular choice for those looking for a healthy alternative to white flour.