Prepare the Sourdough Leaven: Feed the sourdough starter about 8 hours before and ensure it's fully risen.

Mix the Dough: In a large bowl, combine 200g sourdough starter, 600g wheat flour, 400g all-purpose flour, and 700g water.

Mix until the dough forms, and let it sit for 1 hour.

Add Salt and Water: Dissolve 20g salt in 30g water, and fold it into the dough. Perform a stretch and fold by pulling the edges of the dough to the center.

Stretch and Fold Sessions: After 2 hours, do a stretch and fold. Repeat after another 2 hours.

Shape the Dough: Divide the dough into two portions. Shape into round balls and let them rest on the counter, covered, for 1 hour.

Final Shaping: Shape the dough into rectangles and fold into logs for a long loaf, or into rounds for artisan bread.

Proof Overnight: Place the dough in a proofing basket or loaf pan and refrigerate uncovered for 12 hours.

Preheat and Bake: Artisan Bread: Preheat the oven to 450ºF and heat the bread pan for 30 minutes. Flip the loaf into the pan, score, and bake with the lid on for 30 minutes. Remove the lid, reduce the heat to 350ºF, and bake for another 15-20 minutes.

Sandwich Bread: Preheat to 350ºF and bake for 45 minutes.