Ingredients
¼–½ cup bubbly, active sourdough starter 50–100g
1½ cups plus 1 tbsp warm water 375g
4 cups plus 2 tbsp bread flour 500g
1½–2½ tsp fine sea salt 9–12g
Directions
Make the dough: Whisk the starter and water together in a large bowl. Add the flour and salt. Mix to form a rough dough. Cover with a damp towel and let rest for 30 minutes.
Grab a corner of the dough and pull it up and into the center in a stretch and fold motion. Repeat 4–5 times. Let dough rest 30 minutes and repeat. Do this up to 4 times total over the first 2 hours if time permits.
Cover the bowl and let the dough rise at room temperature for about 8–10 hours at 70°F or until it has increased in volume by 50–75%, has a few bubbles on the surface, and jiggles when the bowl is moved. This is the first rise.
Shape the dough by turning the dough onto a lightly floured surface. Fold the top down to the center, turn the dough, and repeat until you've come full circle. Use a bench scraper to create tension.
Let the dough rest seam-side up for 30 minutes. Line an 8-inch bowl or proofing basket. Shape once more and place seam-side up in the prepared bowl.
Cover and refrigerate for 1 hour or up to 48 hours. A 24-hour cold proof produces the lightest, most open crumb. This is the second rise.
Place a Dutch oven in the oven and preheat to 550°F.
Put parchment over the dough and invert the bowl to release. Score the top with a sharp blade. Use the parchment to lower the dough into the preheated dutch oven.
Reduce oven to 450°F. Cover and bake for 30 minutes. Remove the lid, reduce to 400°F, and bake uncovered for 10–15 minutes more until deep golden brown.
Cool on a wire rack for at least 1 hour before slicing.