Step 1: Mix the Dough In a large glass bowl, whisk together your active sourdough starter and the warm water until the starter is mostly dissolved. Add the bread flour and salt. Use your hands or a sturdy spatula to mix until a shaggy dough forms and no dry flour remains. Cover the bowl with a damp cloth and let it rest for 30 to 60 minutes.
Step 2: Stretch and Fold Instead of traditional kneading, we will use “stretch and folds” to build strength. Wet your hand, grab one side of the dough, pull it upward, and fold it over the center. Rotate the bowl and repeat this 4 times. Perform a total of 4 sets of stretch and folds, spaced 30 minutes apart. Cover the bowl between each set.
Step 3: Bulk Fermentation After the final set of folds, cover the bowl tightly with plastic wrap or a damp cloth. Let the dough sit at room temperature for 6 to 10 hours. The dough is ready when it has grown about 50% in size, looks bubbly on top, and jiggles slightly when the bowl is shaken.
Step 4: Shaping the Loaf Gently turn the dough out onto a lightly floured surface. Fold the edges toward the center to create a round shape. Flip the dough over so the seam is down. Using your hands, gently pull the dough toward you on the counter to create surface tension. Let it rest for 15 minutes, then repeat once more for a tighter shape.
Step 5: Cold Proofing Place the shaped dough upside down into a floured proofing basket (banneton) or a bowl lined with a floured kitchen towel. Cover and place it in the refrigerator for 12 to 15 hours. This cold proofing stage develops the flavor and makes the dough easier to score before baking.
Step 6: Preheating and Scoring Place a Dutch oven inside your oven and preheat it to 450°F (230°C) for at least 45 minutes. Carefully flip the cold dough onto a piece of parchment paper. Use a sharp blade or “lame” to make a deep slash across the top of the dough. This allows the bread to expand evenly in the oven.
Step 7: Baking Carefully lower the parchment and dough into the hot Dutch oven. Put the lid on and bake for 20 minutes. The steam trapped inside helps create a thin, crispy crust. After 20 minutes, remove the lid and bake for another 20 to 25 minutes until the crust is a deep golden brown.
Step 8: Cooling Remove the bread from the Dutch oven and place it on a wire cooling rack. It is very important to wait at least 1 to 2 hours before slicing. The bread continues to cook inside as it cools, and cutting it too early can result in a gummy texture.