Pumpernickel is a dense, dark rye bread traditionally associated with Westphalia.
Traditional Westphalian pumpernickel is made chiefly from coarsely ground rye and baked for a very long time at low heat. This extended baking develops its dark color, moist texture, and slightly sweet flavor through slow caramelization and other browning reactions.
The bread is especially associated with the city of Soest and the wider Westphalia region. Historically, its long baking time made it practical to prepare in residual heat after other bread had been baked.
Modern breads sold internationally as pumpernickel can differ substantially from the traditional loaf. Some use finely ground rye flour, coloring, molasses, or shorter baking methods. The name is therefore often used more broadly outside Germany than it is for the classic Westphalian product.