To make the starter: Weigh your flour; or measure it by gently spooning it into a cup, then sweeping off any excess. Mix all the ingredients until smooth. Cover and let rest at room temperature overnight., To make the soaker: Combine the rye chops and water. Cover and let rest at room temperature overnight., The next day, lightly grease the inside of a 13" pain de mie (Pullman loaf) pan, then dust with pumpernickel flour., To make the dough: In a large mixing bowl, combine the starter, soaker, and dough ingredients. Mix the dough, by hand or using a stand mixer, until it becomes dense and sticky, but still loose; it won't require a lot of mixing., Transfer the dough directly to a lightly greased work surface and form it into a 13" log. Place the log in the prepared pan., Sprinkle a thin layer of pumpernickel flour over the surface of the dough, cover with plastic wrap or your favorite reusable cover, and allow the dough to sit for 60 minutes, until just slightly risen. You'll see cracks in the flour on top as the dough expands., Towards the end of the rising time, preheat the oven to 450°F., Uncover the bread and bake the loaf (without the lid on the pan) for 15 minutes, then reduce the oven temperature to 425°F and bake for 50 to 60 minutes longer, until the surface is cracked and dark brown., Remove the bread from the oven, take the bread from the pan, and transfer it to a baking sheet. Bake for another 5 to 10 minutes, until the loaf's internal temperature reaches at least 205°F on a digital thermometer inserted into the center., Remove the loaf from the oven and transfer it to a rack to cool completely. Wrap the cooled bread in a towel, or place it in a paper bag and let it rest for at least 24 to 48 hours before slicing., Wrap in plastic or your favorite reusable wrap, and store in the refrigerator for up to 1 month; freeze for longer storage.