Frisian Black Bread from Ginsberg's "The Rye Baker"

I just finished creating my first bread from Ginsberg's book. All seemed to go well with the recipe until the end of the bake. Nice rise, nice oven spring, really nice smell as it baked. Everything.

Here's the timing of my bake:

1. 20 min for the oven to reach (nominal) 460 F.
2. 20 min at that high temp, after which I turned down to (nominal) 375 F.
3. 25 min later the top was looking very dark, so I tented with foil.
4. 15 min after that, I removed from oven.

So that's a total of 80 min from the time I turned oven on until I turned it off.

BUT... when I did take the bread out, the top crust was so hard that it was difficult to get my Thermapen Mk 4 to pierce it. And when I finally did get it through the roof armor, I read an internal temp of 208 F.

I immediately boiled up some water and painted a liberal coat onto all six faces.

I hope that after all the time and effort—and anticipation—I haven't turned it into a lead-lined cinder.

I was also irked by an instruction that I find to be quite ambiguous. Ginsberg's guidance for how to proceed after you've turned the oven down reads thus:

"continue baking until the loaf thumps when tapped with a finger and the internal temperature is at least 198F/92C, 75–80 minutes." [emphasis added] 

My intuition told me that 75 or 80 add'l minutes after the 40 min was a lot, but for all I knew, this was just one more way in which the Wonderful World of Rye differed from my decades of experience confined to Wheatland. Now I'm thinking he may have meant "75–80 minutes total," which is to say, "a further 35–40 minutes."

I don't believe that my oven runs particularly hot, since most of the time I find that the times given in others' published recipes are pretty close to what I do need. I'm wondering if this is just one more example of the, umm, eccentricities in Ginsberg's instructions. My next opportunity to gather more data on that point will come two days hence when I slice into the thing.

Be that as it may, I should have known to check the temp sooner, especially because I had seen that the top crust was getting darker than I'd have expected. But again in my defense, I figured, "For all I know, this is why it's called 'black' bread."