Purple Sweet Potato Sourdough Bread

1. In a large bowl, combine 300g bread flour, 3g purple sweet potato powder, and 234g water (78% hydration). Mix until no dry spots remain, then cover and let the mixture autolyse for 3 hours.
2. After autolyse, incorporate 60g levain (20% of flour weight) and 6g salt (2% of flour weight) into the dough. Mix thoroughly until the ingredients are well distributed.
3. Perform 1 round of stretch and folds, followed by 3 rounds of coil folds throughout a total bulk fermentation period of 6 hours. The exact timing between folds will depend on your dough's activity.
4. Gently shape the dough into a taut ball and transfer it to a floured proofing basket or bowl. Place it in the fridge for 18 hours overnight for a cold proof.
5. The next morning, preheat your oven to 500F (260C) with your Dutch oven inside for at least 30 minutes.
6. Once preheated, carefully score the cold dough and transfer it into the hot Dutch oven.
7. Bake with the lid on for 25 minutes at 500F (260C).
8. Remove the lid, reduce the oven temperature to 450F (232C), and continue to bake for an additional 20 minutes, or until the crust is deeply golden brown and cooked through.
9. Carefully remove the bread from the Dutch oven and let it cool completely on a wire rack before slicing.