Caramel Color

• Adding caramel color makes pumpernickel bread dark. You can purchase this coloring agent, or you can make your own by burning sugar until it reaches your desired color and dissolving it in water. You can use this dark-colored water as some of the liquid in your recipe.

Other Coloring Agents

• Adding a bit of unsweetened cocoa powder, coffee or both -- in the form of espresso powder, brewed coffee or instant coffee -- also darkens pumpernickel bread. With their slightly bitter tastes, these ingredients also add depth to the bread's flavor. You can achieve the bread's characteristic bitter-sweetness by adding a bit of molasses.

Altus

• Using stale pumpernickel bread in your recipe also can contribute to the loaf's color. Called altus, stale pumpernickel bread soaked in water adds moisture and flavor, as well as color, to your loaf. You can add these soaked crumbs to your recipe's liquid before mixing the dough.

Baking Time

• Baking pumpernickel bread for long periods of time, at a low temperature, gives more time for the sugars in the rye flour to caramelize. These natural sugars darken and provide a subtle hint of sweetness to the bread. To achieve a dark color and subtle flavor, bake the bread at a temperature as low as 200 degrees Fahrenheit for around 6 hours.