Prepare the leaven. Mix the starter and water in a small jar or bowl. Add the flour and mix until there are no more dry lumps. Cover and proof at 80ºF for four hours. The leaven is ready to use when it has doubled in size, looks really active, and has bubbles breaking on the surface.
Make the dough. In a large bowl, add the leaven and 600 grams of warm water. Stir to break up the leaven. Add the remaining flours and mix. Knead the dough by hand until there are no more dry bits of flour (it will be very sticky). Scrape down the sides of the bowl, cover, and rest for 30 minutes. Sprinkle 18 grams of salt on the surface and pinch into the dough with a wet hand. Continue to mix until all of the salt has dissolved. Cover again and rest in a warm spot for 4 hours of bulk fermentation.
Bulk fermentation. While bulk fermenting, you will need to stretch and fold the dough every 30 minutes. With a wet hand, scoop one quarter of the dough from the bottom of the bowl. Stretch upwards as far as it will naturally pull and fold it back onto the center of the dough. Rotate the bowl and repeat three more times, so that all of the dough has been stretched. Cover and place the bowl back in a warm spot to continue proofing.
Dividing the doughAfter the four hours are up, the dough will have grown substantially and will have a very supple texture. At this point, quickly scrape the dough from the bowl onto a floured surface with a bowl scraper. Divide the dough into six pieces with a bench scraper. Starting with one portion of the dough, bring the top, bottom, left, and right sides to the center-starting to form a ball. Bring the remaining four corners to the center, tightening the shape. Use the bench scraper to pick up the dough and flip it over onto the seam. Gently round the ball with the side of your hand and the bench scraper. Let the dough rest for 30 minutes.
Shaping the doughTo form the dough into the final boule shape, flip one of the dough balls onto a well floured surface. Loosen the top and bottom corners to from a long rectangular shape. Pull the top edge down to the center. Pinch a small amount of dough from the left and right sides and bring to the center. Overlap the dough as you work your way down, like you are stitching the seam together. Once you get to the bottom, tightly roll the dough up towards the top. Use a bench scraper to flip the dough over. Roll the dough between the edges of your palms to tighten and form more of a ball shape.
Final ProofFor the final proof, you will need cotton or linen napkins and soup bowls. Line the bowls with the napkins and generously dust with flour. Once the bread is rolled into the final shape, transfer into the lined bowl and fold over the flaps of the napkin to cover the dough. Once all six portions are covered, place in the refrigerator to proof overnight.
Scoring and BakingPre-heat your oven to 475º F with a ceramic baking stone on the middle rack and a heavy metal sheet tray on the bottom rack. When you are ready to bake the first batch of bread bowls, (it will bake in two batches) transfer three rounds of dough onto a sheet of 12×16” parchment paper set atop a wood peel. Sprinkle over flour and quickly make four slashes (to form a box) with a bread lame or razor blade. For an extra flourish, I like to add a wheat design to the center.To bake, quickly slide the parchment paper off the peel onto the hot baking stone. Pour 1/2 cup of ice onto the hot baking tray. The steam will form a beautiful crust. Bake at 475ºF for 25 minutes.
Allow the bread to cool completely before serving for the best texture.
How to Serve the Sourdough Bread BowlsTo turn the boules into bread bowls, cut into the bread along the square design. A serrated knife works best for this job. Try to cut at an angle (towards the side of the bowl) so you have lots of room for the soup. Pull off the top and scoop out any extra bread. Ladle in your favorite soup and serve with the lid! As you finish the soup be sure to pull off pieces of bread to enjoy!
For best results, feed your starter 8 hours before making the leaven.
Allow the bread to cool completely before serving.
Store any unused bread in a bag at room temperature for a week, or wrap tightly and store in the freezer for one month