Mix the Dough: In a large mixing bowl, combine the water (325g), active starter (100g), salt (10g), and flour (475g). Stir with a wooden spoon or mix with your hands until the ingredients are well combined. Cover the bowl and let the dough rest for 30 minutes to let the flour fully absorb the water.
Stretch and Fold: After resting, uncover the bowl. Gently grab an edge of the dough, stretch it upwards, then fold it over to the center. Turn the bowl a quarter turn and repeat the stretch and fold. Cover the dough and let it rest for another 30 minutes. Repeat the stretch-and-fold process two more times, with 30-minute rests in between each round.
Bulk Ferment: Once you’ve finished the stretching and folding rounds, cover the bowl with a lid or damp towel. Allow the dough to bulk ferment in a warm spot until it doubles in size. Depending on the temperature of your kitchen and the activity level of your starter, this can take anywhere from 6 to 12 hours.
Pre-Shape the Dough: Transfer the dough to a lightly floured work surface. Gently fold the dough into itself and roll it up, shaping it into a smooth ball by lightly spinning it toward you. Let the dough sit uncovered for about 15–20 minutes.
Final Shape: Flip the dough over, stretch each side of the dough to flatten it out. Fold the edges of the dough onto the center and roll it into a ball. Then, build surface tension by gently pushing the dough away, cupping the backside, and pulling it back while dragging against the counter. Make sure to stop before you see any ripping. Repeat 5-6 times until you have a tight ball. Place the dough, seam side up, in a floured banneton or a bowl lined with a well-floured tea towel
Bake: Preheat your Dutch oven in the oven at 500°F (260°C) for an hour before you’re ready to bake. Remove your dough from the fridge and transfer it onto a piece of parchment paper or bread sling. Dust the dough with a bit of flour and score it with a sharp blade or a lame. Carefully lift the dough, along with the parchment paper, into the hot Dutch oven. Place the lid on and lower your oven to 475°F (260°C) bake for 20 minutes. After 20 minutes, carefully remove the lid, reduce the oven temperature to 450°F (245°C), and bake for another 15–25 minutes, or until the crust is a deep golden brown.
Cool and Enjoy: Allow your sourdough to cool on a wire rack for at least an hour before slicing—this lets the interior finish setting, giving you a beautiful crumb structure inside. Now, slice, slather with butter, and enjoy the fruits of your labor!