Rye flour has an especially high level of activity in sourdough bread when compared to other flours.
Rye offers an extremely complex flavor profile, and bodes particularly well to long and slow sourdough fermentation.
If you’ve ever eaten a 100% rye bread, you’ll have definitely noticed that it is dense, dense, dense!
Sourdough bread tends to have a slightly drier texture than yeasted breads, but rye helps to bring back some of that moistness.