Pumpernickel is a typically heavy, slightly sweet rye bread traditionally made with sourdough starter and coarsely ground rye. It is sometimes made with a combination of rye flour and whole rye grains .
At one time it was traditional peasant fare, but largely during the 20th century various forms became popular with other classes through delicatessens and supermarkets. Present-day European and North American pumpernickel differ in several characteristics, including the use of additional leaveners. The North American version may have coloring and flavoring agents, added wheat flour, a higher baking temperature, and a dramatically shortened baking time.