Leaven. Mix starter, flours, and water until just incorporated. Seal, and
rest at room temperature for 8-10 hours.
Autolyse. Blend the flours until homogenous. Add water, and mix until
just incorporated. Cover and rest 45 minutes.
Mix soaker. Combine oats and water, cover, and rest 45 minutes.
Mix. Add salt, yeast, soaker, and leaven to the autolysed dough, and mix
by hand using the
pincer method. The temperature
after mixing should be 25ºC-26ºC (77ºF-78ºF).
Bulk fermentation. Rest 1h 30m. Slap & fold a few times. Rest an
additional 3h 30m until the dough is 2.5x its original volume.
Shape into a medium-tight ball. Arrange seam side down for proofing.
Proof (optional) 12-14 hours in the refrigerator in a non-perforated
plastic bag.
Preheat oven to 250ºC (482ºF).
Preheat dutch oven with its lid at least 45 minutes.
Bake 30 minutes covered. Remove lid, and continue baking 20 minutes until
dark brown all around the loaf.
Cool loaf at room temperature at least 20 minutes.