Wild Yeast Bread is beautiful and unruly all at once. Instead of using a leavening like a sourdough starter or commercial baker's yeast, fizzy and bubbly yeast water leavens this bread, resulting in an artisan-style boule that's delicious, if a bit unpredictable. Remember, you'll need plan about five days in advance to make the starter for this bread.
Measure the flours into a large mixing bowl, and then stir them together.
Pour the wild yeast starter into the bowl, and then stir it together with flour to form a loose, shaggy dough. Cover the bowl tightly with a lid, or a stretch of plastic wrap. Allow the dough to rest for about 30 minutes.
Salting the dough and bench rise.
Sprinkle the salt over the dough, and then drizzle in the water. Knead the salt and add the water into the dough, and then cover the bowl once more.
Let it rise about 1 hour, and then lift the lid and stretch the dough over itself. Repeat this process four times over the next 2 hours. Then, let the dough rest undisturbed until doubled in bulk - about 2 more hours.
Shaping and final rise.
Dust your working surface with flour, and then tip the dough out of its bowl onto the floured surface. Gently press it down into a loose rectangular shape. Fold the corners in over themselves, and then shape the dough into a boule.
Transfer the dough to a well-floured banneton and cover it loosely with a tea towel, and then let it rise about another 2 hours. Gently press a fingertip into the dough, applying about as much pressure as a penny. If it bounces back, let it continue to rise. If the pressure of your fingertip leaves a dent in the dough, transfer it to the fridge.
Baking the bread.
While the dough rests in the fridge, place a Dutch oven into the oven and set the temperature to 500 F.
When the oven reaches temperature, cut a square of parchment paper about 12 by 12 inches.
Turn the dough out of the banneton onto the parchment paper, and then score the dough using a bread lame or a sharp kitchen knife.
Remove the Dutch oven from the oven, and carefully remove the lid. Holding the edges of the parchment paper, gently lower the dough into the Dutch oven. Return the lid to the pot, and transfer it back to the oven.
Turn down the oven's heat to 450 F, and bake for 30 minutes.
After 30 minutes, lift the lid of the pot and continue baking the bread a further 15 to 20 minutes or until golden brown. Transfer to a cooling rack and let the bread cool completely before slicing and serving.