As good and authentic a rye bread recipe as we have to work with this week, there are a couple of dead giveaways that we’re dealing with “citified” rye. One is of course the leavening: it’s packaged yeast. No northern European peasant would have had anything like that to work with back in the day. Instead, they’d have had to make do with a wild yeast starter, either a soupy wild yeast “barm” or a piece of old dough from the previous day’s batch. This of course would have added a lot of flavor, but also made the bread very dense. Most real ryes are still made in this way.
Next, it’s colored and sweetened with molasses. True peasant rye breads didn’t need coloring, since they were made from coarse-ground, whole meal rye flour. The bran from the rye kernels colored the bread grey-brown. Today’s rye flour is made from just the endosperm of the kernel, and so needs to be colored in some way (otherwise the finished bread turns out a kind of sickly pale grey). Yet the deep color and relative sweetness of old-world “black” rye bread was also a result of the way they baked it. Authentic pumpernickel ryes are baked at extremely low temperatures which means they spend a great deal of time in the oven (up to 24 hours if you can believe it). All that baking time gives the sugars in the dough (and there are plenty of them…remember those sugar-making enzymes I was talking about yesterday?) plenty of time to caramelize. As they do they turn the bread a deep coffee brown. Neat.