Wikipedia Article About Pumpernickel bread on Wikipedia Traditional German pumpernickel contains no coloring agents (such as molasses), instead relying on the Maillard reaction to produce the characteristic deep brown color, sweet dark chocolate coffee flavor, and earthy aroma. Loaves produced in this manner require 16 to 24 hours of baking in a low temperature (about 250°F or 120°C) steam-filled oven. They tend to have a much more intense flavor than the approximations provided by adding molasses, coffee, cocoa powder, or other darkening agents employed by many bakeries.