The night before, make the Levain and the Soaker:  Combine the ingredients for the Levain in a medium bowl.  Stir with a spoon to combine (mixture will be thick and the texture of wet cement).  Cover with plastic wrap and leave at room temperature overnight, approximately 12 hours.  Combine the ingredients for the Soaker in a small bowl.  Cover with plastic wrap and leave at room temperature overnight, approximately 12 hours.

The next morning, grease a 13 x 4 inch pullman loaf pan (with a lid) and dust it with rye flour.  Set aside.  

Combine the Levain and the Soaker (no need to drain) in the bowl of a heavy duty stand mixer.  Add remaining dough ingredients. Using the paddle attachment, mix on low speed for 3-4 minutes, scraping down the sides of the bowl occasionally.  Increase speed to medium and continue to mix and periodically scrape down the sides of the bowl for another 4 minutes.

Using a sturdy spoon or spatula, transfer the dough to the prepared loaf pan, distributing it evenly across the length of the pan and smoothing out the top with a rubber spatula (if you are having trouble smoothing out the top, dampen the spatula slightly with water).  Dust the surface of the loaf generously with rye flour. Put the cover on the loaf pan and let it rise until it comes to within a ½ inch of the top of the pan. This may take anywhere from 1 ½-4 hours depending on the temperature of your kitchen and the dough.

Meanwhile, preheat the oven to 500 degrees.  Place the covered loaf pan in the oven and bake for 15 minutes.  Reduce the temperature of the oven to 400 degrees. Bake, covered, for an additional 15 minutes.  Pull the loaf pan from the oven and remove the lid. Reduce the temperature of the oven to 325 degrees and continue to bake, uncovered, for an additional 45 minutes.  Remove loaf from the oven and tip out onto a wire cooling rack. Let cool completely before slicing. Rye breads improve after a bit of resting time. If you can wait until the following day to slice into it, wrap the completely cooled loaf loosely in foil and let it cure until the next day.  The bread will keep for about 4 or 5 days at room temperature wrapped loosely in plastic wrap and a layer of foil. For longer storage, wrap tightly and freeze.