Adapted from America's Test Kitchen Bread Illustrated.
The original recipe calls for toasting the wheat germ, I opted not to and it tasted fine to me, I will try it again and toast it but I don't think it's necessary.
Make the soaker.
Stir all the ingredients in a large bowl with a wooden spoon until shaggy mass forms. Transfer to a lightly floured surface and knead by hand until smooth, about 3 minutes. Return soaker to bowl, cover tightly with plastic wrap. Refrigerate for at least 8 hour, or up to 24 hours. (It may be a bit sticky.)
Make the sponge.
Stir all ingredients in a bowl with wooden spoon until well combined. Cover tightly with plastic wrap and let sit at room temperature for about 6 hours. It can sit at room temperature for up to 24 hours.
Tear soaker into 1-inch pieces and place in the bowl of a stand mixer with your dough hook attached. Add sponge and remaining ingredients for the dough. Mix on low speed until cohesive dough starts to form. Increase speed to medium low and knead until dough is smooth and elastic, about 8 minutes. Transfer dough to lightly greased large bowl, cover tightly with greased plastic, and let rise for about 45 minutes.
Fold the dough over itself by gently lifting and folding edge of dough toward middle. Turn bowl 45 degrees and fold, repeat making a total of 8 folds. Cover tightly with plastic and let rise until nearly doubled in size, 30 minutes to an hour.
Grease two loaf pans. Press down on dough to deflate. Transfer dough to lightly floured counter and divide in half. Shape each half by stretching dough into 8X6" rectangle and rolling into firm cylinder. Pinch seams closed and place loaf crease side down in prepared plan. Cover loosely with greased plastic and let rise until loaves reach 1" above top of pan, about 1 - 1.5 hours.
Preheat oven to 350 degrees. Use a sharp paring knife to make a single 1/4" deep slash lengthwise across the top. Mist loaves with water.
Bake for 40-45 minutes. Let loaves cool in pan for 15 minutes and then remove from pans to cool completely on wire rack.