01 - In a large bowl, combine the bread flour, whole wheat flour, and water. Mix until just incorporated. Cover the bowl and let rest for 1 hour to hydrate the flour.
02 - Add the active sourdough starter and sea salt to the autolysed dough. Mix by hand or spatula until fully integrated and no dry flour remains.
03 - Cover and ferment at room temperature for 4 to 5 hours. Perform stretch and folds every 30 to 45 minutes, repeating 4 times to develop gluten structure.
04 - Turn the dough onto a lightly floured surface. Gently shape into a round boule. Cover and let rest for 20 minutes to relax the gluten.
05 - Shape the dough into a tight round loaf. Place seam side up in a well-floured proofing basket or lined bowl.
06 - Cover and proof at room temperature for 2 to 3 hours. For enhanced sour flavor, refrigerate overnight for cold proofing.
07 - Position a Dutch oven or heavy pot with lid in the oven. Preheat to 480°F for at least 30 minutes to ensure proper heat retention.
08 - Gently invert dough onto parchment paper. Score the surface with a sharp blade or lame. Transfer to preheated pot, cover, and bake for 20 minutes. Remove lid, reduce temperature to 430°F, and bake 25 minutes until deep golden brown.
09 - Remove bread from pot and transfer to a wire rack. Cool completely before slicing to ensure proper crumb structure.