1Add active starter, salt, and filtered water to a bowl.
2Stir the mixture.
3Add unbleached bread flour to the bowl.
4Mix it until your dough looks shaggy.
5Cover the dough and let it proof or rise for 30 minutes.
6Perform the first stretch and fold by grabbing the dough and folding it over. Repeat this four times.
7Cover the dough and set a timer for 30 minutes. You will do a total of three sets of stretch and folds.
8Cover the dough and leave it on the counter all night long.
9Shape the dough into a loaf by spreading it out like a piece of paper, folding it like a letter, and then rolling it up.
10Build tension and strength in your loaf by cupping your fingers, grabbing the loaf, and pulling it towards you, doing this a couple of times until you have a nice, smooth surface on the top.
11Dump the shaped loaf upside down into a proofing basket or a bowl, and let it proof for about 30 minutes while the oven preheats.
12Preheat your Dutch oven in the oven at 450 degrees Fahrenheit for 30-60 minutes.
13Carefully place the dough into the preheated Dutch oven.
14Score the top of the loaf.
15Bake at 450 degrees Fahrenheit for 30 minutes with the lid on.
16Reduce the heat to 425 degrees Fahrenheit and cook for an additional 10 minutes, leaving the lid on.
17Remove the bread from the oven and let it rest for 30 minutes before cutting into it.