Combine the whole-wheat flour and water in a bowl. Stir until well combined. Place in the refrigerator until needed, 12-24 hours.

Combine the poolish ingredients in the mixing bowl that you will use for the final dough (e.g., the bowl of a stand mixer) and mix with a spoon until thoroughly combined. Cover and let sit at room temperature for 12-24 hours.

Some time before you are ready to mix the dough, take the soaker out of the refrigerator so it can warm up. Every now and then, give the soaker turn and stir so that different parts contact the outside surface of the container (and therefore warm up faster). If you are in a hurry, put the soaker in a metal bowl and put the bowl into warm water.

If you are using instant yeast (the kind that doesn't need to be dissolved in liquid), you will add it with the first batch of dry ingredients. If you are using regular active dry yeast, you will rehydrate it in some warm water before adding with the water, honey and oil.

Cut the soaker into unshelled walnut-sized pieces and add to the poolish. Add the water, honey, butter or oil (and non-instant yeast and its rehydrating water). If using a stand mixer, use the paddle attachment to mix these gooey ingredients together. If mixing by hand, use a wooden spoon.

Add the rolled oats and bran (and instant yeast). Salt will be added later. Switch to the dough hook, mix on low speed until thoroughly combined.

Add the white flour, and knead on medium for 4 to 5 minutes. The dough should be a little sticky, but hold together as a mass. Add a little more flour if it is really sticking to the walls of the bowl.

Now it is time for the autolyze, a short resting period that helps build gluten. Cover the bowl and let the dough sit for 10 minutes.

Uncover the bowl, turn on the mixer to low, and add the salt a little bit at a time. Increase the speed to medium and continue mixing for a few more minutes to fully incorporate the salt and build structure.

Place the kneaded dough in a lightly oiled bowl and cover. Let rise for about 1 hour or until doubled.

Grease two standard-size bread loaf pans (5" x 9").

Punch down the dough, divide in half and shape into two loaves. Place in the prepared loaf pans. Cover and let rise for 45-60 minutes.

During the last 30 minutes of the second rise (or 45 minutes if using a pizza stone or bricks), preheat the oven to 375 F (190 C).

Make 2-3 cross-slashes or one longitudinal slash on the loaf just before baking.

Place the loaf pans on the rack or on the pizza stone or bricks,

Bake for about 45 minutes, rotating the pans halfway through baking to provide even heat.