Ginsburg's formula for Black Bread of Lithuania at theryebaker.com calls for "Whole Rye Flour". He adds this: NOTE: If you can’t find whole rye flour, use a blend of 2/3 medium and 1/3 dark rye flour.
I don't understand what he means by whole rye flour. I would have thought it meant 100% extraction rye flour, like https://www.bobsredmill.com/product/organic-dark-rye-flour for a fine grind or Fair Haven Mill Coarse Rye Flour for pumpernickel.
But Ginsburg writes that you can substitute a blend of medium and dark rye. What's up with that?
I mixed the sponge and scald for the bread this morning using the blend. I'll probably mix the final dough tomorrow with the Fairhaven pumpernickel, unless somebody explains why the blend would be better.
Ginsburg has a table in The Rye Baker on page 29, and this table is repeated in his post
theryebaker.com/rye-flour/
He shows "whole grain" being between "medium" and "dark". He gives ash and protein values. But the big point in the post is that since rye flour isn't standardized in the US, you never know what you will be getting from any particular US mill.
His "dark" rye is equivalent to the Austrian grade "R2500" if that's any help (it isn't to me).
TomP
Ginsberg had a retail outlet (NYBakers) that sold rye products. Most (all?) of these rye flours and meals were from Bay State Milling. I had some of the dark rye from NYBakers and it was definitely different from any whole (100% extraction) rye flour I have used (Bob's RM, Breadtopia, Janie's Mill, and an imported rye from Serbia). I have to assume that the BSM dark rye was close to the Austrian R2500.
As Tom mentioned, Ginsberg uses the term "dark rye" to describe the dark rye flour from Bay State Milling that approximates the Austrian R2500. Other "dark rye" flours, like Bob's RM, are just whole (100% extraction) rye. Ginsberg blends the dark and medium rye to approximate the ash content of whole rye. If you have 100% extraction rye flour, I would use it. That's what I used when I have made that bread. BTW, it's delicious!