It depends on which side of the Atlantic you stand. Old World German Rye Bread, known as Roggenbrot, contains only rye flour. It is almost always made with rye sourdough, and has a rough, notably rustic texture. Schwarzbrot (German black bread) and traditional pumpernickel rye bread fall into this category. This dark rye bread recipe contains both wheat and rye flours and is leavened using baker's yeast. This softer, hybrid-style dark rye is what you are likely most familiar with if you live the in the US. It is known in Germany as Roggenmischbrot (mixed rye bread).