Pain au Levain Naturel

1. Feed your starter 4 to 8 hours ahead so it is bubbly and doubled, then in a large bowl combine the bread flour, whole wheat flour, and 330 g of the water, mixing until no dry flour remains, and let this shaggy dough rest, covered, for 45 minutes to autolyse.
2. Add the active starter and the salt dissolved in the remaining 20 g of water, then squeeze and fold the dough until fully incorporated and slightly tacky, adding the extra water only if it feels stiff.
3. Bulk ferment at warm room temperature for 4 to 5 hours, performing a set of stretch-and-folds every 30 minutes for the first 2 hours, until the dough is smooth, domed, and risen by about half.
4. Turn the dough onto a lightly floured surface, pre-shape into a round, rest 20 minutes, then shape tightly into a boule or batard and place seam-side up in a floured banneton.
5. Cover and proof in the refrigerator for 12 to 16 hours, which develops flavour and makes scoring easier.
6. About 45 minutes before baking, place a Dutch oven inside your oven and preheat to 250 degrees C, then turn the cold dough out onto parchment and score the top decisively with a sharp blade.
7. Bake covered for 20 minutes, then uncover, lower the heat to 230 degrees C, and bake a further 20 to 25 minutes until deeply browned and the internal temperature reaches at least 96 degrees C; cool completely on a rack for at least 1 hour before slicing.

You'll use: Oven