It is best if you use a kitchen scale to measure ingredients. It works best if it is measured by grams.
Place a large glass bowl on a kitchen scale and set to "0".
Add 90 grams of active sourdough starter to the bowl.
Add 350 grams of warm water. Use a whisk to mix the starter and water.
Add the flour and salt.
Use a sourdough spoon (or a rubber spatula) to mix the ingredients together to form a rough, shaggy dough.
Allow this dough to sit for 30 minutes. (This is the autolyse stage.)
Work the dough into a ball, which should only take about 15 seconds. Place the dough back in the bowl. Cover the bowl with plastic wrap and place the bowl in a warm spot to rise. This could be in indirect sunlight or in an oven with the light on. Or you can just let it sit on the counter if you keep your house warm.
Allow the dough to rise until the dough has almost doubled. This usually takes about 8 hours for us, but it will depend on how active the starter is and the temperature of the ingredients. (Most people plan for anywhere from 4-12 hours for this bulk fermentation.) If you have your dough in a glass bowl you should be able to look through to see bubbles forming all in the dough.
Carefully pull the dough out of the bowl. If it feels really sticky you may want to sprinkle the counter lightly with flour. The dough will gently deflate which is ok. You want to be careful not to punch it down or work the dough too much at this point.
Start on one side and fold the dough over. Then turn the dough slightly and fold over the next section of dough towards the center. Turn the dough again and fold again, then do it again until you've gone all the way around the circle. This process creates a surface tension on the outside of the dough for a nice shape.
Place the dough smooth side down in a floured banneton basket.
Allow the dough to rise one last time. This last rise will take anywhere from 1-3 hours. The dough should look slightly "puffy" again and light textured (not dense), but does not have to be doubled. It will rise nicely in the oven.
Preheat the oven to 450º Fahrenheit.
Cut a piece of parchment paper and lay it on the counter. Turn out the dough onto the parchment paper.
Place the dough ball (with parchment paper) into a dutch oven. Place the dutch oven cover on.
Turn the oven down to 425º Fahrenheit. Then bake the bread in the covered dutch oven for 40 minutes. Remove the cover and continue to bake for another 10 minutes or until the bread is golden brown.
Remove from the oven and allow the bread to cool completely on a wire rack.
This bread will have the best flavor when it is served the next day, but it is also so good fresh from the oven. For the best texture you'll want to wait at least an hour before slicing the bread with a strong serrated knife.
Store the bread in an airtight container.
*If the dough is too sticky for the environment you live in, reduce the water by 25 grams and/or increase the flour. 99% of the time, we make the recipe as written, adding in up to 1/2 cup more flour for kneading, as stated. It is definitely a sticky dough which is the way we like it, but you can totally add more flour if you'd like.The calories shown are based on the bread being cut into 16 pieces, with 1 serving being 1 slice of bread. Since different brands of ingredients have different nutritional information, the calories shown are just an estimate. **We are not dietitians and recommend you seek a nutritionist for exact nutritional information.**