We would argue that, yes, there is definitely a difference. Or at least there should be! After paging through several of our favorite bread baking books, here's what we've determined:
Light Rye: This bread is made using white rye flour ground from the center endosperm of the rye berry. This flour does not contain any of the outer seed coat, the bran, or the germ, so the flour (and the bread it eventually makes) stays fairly light in color.
Dark Rye: From what we can tell, dark rye breads can be made in one of two ways. The first version uses white rye flour and the same basic formula as light rye bread, but adds coloring and flavoring agents like molasses, cocoa powder, or instant coffee.
The second, and likely more historically authentic, version uses a different grind of rye flour than light rye loaves. This flour is milled from the outer endosperm, which contains more of the coloring pigments from the rye berry. This flour also tends to be ground more coarsely.
Pumpernickel: Real pumpernickel bread is made using a specific kind of flour called, appropriately enough, pumpernickel flour. This flour is made from coarsely-ground whole rye berries. In some traditional recipes, breadcrumbs left from other rye loaves are added to the dough for pumpernickel bread.
Pumpernickel loaves tend to be dense, dark, and strongly flavored. We think they're best enjoyed when sliced very thinly and preferably with a shmear of cheese and some thin-sliced smoked salmon!
Marbled Rye: This bread is simply a bit of light rye dough and a bit of dark rye dough braided or rolled together. These two breads have nearly the same density, so they bake together into a uniform texture.
We should also point out that almost all rye breads have a certain percentage of wheat flour added to the dough. Rye has almost no gluten-producing proteins of its own, so additional help is needed to produce an edible loaf.
Are you a fan of rye breads? What's your favorite way to enjoy it?