Some of Hamelman's recipes in Bread call for "Medium Rye". I can get locally grown and milled, whole grain rye and have used this when called for. I also have some Bob's Red Mill "Dark Rye". Is the latter equivalent to Medium Rye (I assume that bob probably sifts out some of the whole grain flour to improve shelf life)?
What do you think is the retail equivalent of Medium Rye?
BRM "Dark Rye" isn't the same as medium rye. I use King Arthur Flour's "Rye Flour" when a recipe calls for medium rye flour. P. 42 of Hamelman, 2nd ed. gives some description of the types of rye flours.
Bob's Dark Rye is just a regular whole rye flour. Medium rye is medium rye. Some older books rely on it heavily because it used to be common retail flour made by Pillsbury. In mixed breads with low rye percentage you can probably substitute it 1:1 and don't give another thought. For high percentage ryes you may want to get the right stuff to at least see what the difference is.
The label in the photo above says "milled closer to the bran". I assume that means it's a higher extraction rye flour than, say 'white' rye flour. Not a coarse whole rye, but also not sifted down to the endosperm.
Many German and European rye breads require medium rye. It can't be substituted with dark rye, unless, as Suave said, the percentage of it is fairly small.
You can mix dark/whole rye flour (75%) with white rye (25%) to achieve approximately the same flour type, but I would rather recommend to get the real thing from King Arthur, NYBakers, or Honeyville, especially if you want to bake rye breads more often.
Karin