Morning: Combine the flour, water, yeast, and sourdough, if using, in a bowl, mixing together with a spatula or your hand moistened with water for about 1 minute. After the ingredients are combined, make a small indentation on the top of the dough. Add the salt to the small well you've just made in the dough, and about 1 tablespoon of water to cover it, but don't mix it in yet. Cover the bowl and let the dough sit for 20 minutes. Moisten your hands slightly and use the dough scraper to loosen the dough from the bowl. Rather than knead the dough, you're going to stretch and fold it in the bowl. Working from the edges of the dough, pull the dough out to stretch it and then fold it over toward the center. You can also squeeze the dough with your fingers to help incorporate the salt. If your hands begin to stick to the dough, moisten them again with water. Work around the dough and stretch and fold it 12 times. This action should take about 1 minute in total. Flip the dough over so the folds are underneath and the smooth side is on top. Cover the bowl and let the dough sit for another 20 minutes. Do the stretch-and-fold action for one more round. By now you'll notice that the salt is incorporated and the gluten offers noticeable tension. After folding about 12 times, turn the dough over again, cover the bowl, and let the dough rest for 20 minutes. Do the stretch-and-fold action 2 more times, at 20-minute intervals. In the final round, the dough should feel very elastic and should be glistening. If it isn't, add a few more stretch-and-fold actions but be careful not to rip the dough. Turn the dough over so the smooth side is face up. Cover the bowl and let it sit for 6 to 7 hours. The goal here is for the dough to rise until it has at least tripled in size, but has not collapsed in on itself. By the end of the rise, you might see big air bubbles on the top of the dough.
Afternoon: Preheat the oven to 470 degrees F (245 degrees C), with your baking stone on the middle rack, 60 minutes before baking. In the lower part of the oven, or on the bottom, place a rimmed baking sheet that can hold half a cup of water. Place a piece of parchment paper roughly the size of your baking stone on an overturned and lightly floured baking sheet or a cutting board. Dust the parchment lightly with a 50/50 mixture of white flour and semolina flour or just white flour and set it aside. Flour a two-foot-square area of your counter generously with the flour/semolina mix or white flour. Dust the top of the dough lightly with flour. Using a plastic dough scraper, gently loosen the dough from the bowl and pour it out onto the counter, being careful to keep it in one piece. The outer, smooth surface will have landed on the floured surface, becoming the bottom of the dough. The top of the dough will be sticky. Dust it lightly with flour. Flour your hands and gently make a rectangle that's about 3/4 to 1 inch thick and about 10 by 16-inches, with the long side on the east-west axis, or parallel to the edge of the counter. Don't fuss over it to make it perfect or you'll compress the dough, losing the open structure of the air holes. Sprinkle a thick line of flour across the middle of the dough, moving east-west, marking where you will divide the rectangle in half lengthwise. Then sprinkle another two lines of flour through each of those portions, again moving east-west. You will cut the dough along the three lines, making four long loaves. Using a dowel, the wooden handle of a kitchen spoon, or a chopstick, press on the floured line so the pieces separate. A thick, dull tool works well because it joins the dough together at the seam. If the tool does not fully cut through the dough, use your dough scraper to finish cutting the pieces. Separate the pieces so they are not touching each other and cover them with a light towel. This second fermentation will take about 20 minutes. When the loaves are ready, they will be very light and spring back within one second when you press your finger very lightly into the dough.
Baking: Pour 1/2 cup water into a measuring cup. Sprinkle the loaves lightly with semolina/flour. Loosen two loaves gently with the dough scraper. If you put enough flour on the counter it won't take much effort. Place your hands under the dough at either end of one loaf, then turn it upside down onto the floured parchment paper. To prevent the dough from sagging in the middle while you move the loaf, you can move your two hands closer together, slightly crimping the loaf lengthwise. The floured underside is now facing up. Do this with the second loaf, too. (If your baking stone is big enough, you might be able to place all four loaves on the parchment paper and bake them at once.) Now, here's the fun part. Lightly grab either end of the dough and gently stretch out the loaf to just under the size of your baking stone. If it resists, don't pull it-the dough will rip. Do the same with the second loaf. You can straighten out the edges by gently repositioning the loaf with your dough scraper, but don't fuss too much. Open the oven and slide the parchment paper off the cutting board or baking sheet and onto the baking stone. The loaves will bake on the parchment paper the entire time. Close the oven. Take the 1/2 cup water and pour it onto the baking sheet, being careful not to get burned by the steam. Shut the oven door. Bake for 18 to 22 minutes. Do not open the oven until at least 18 minutes into the bake. Bake until dark brown. Using a peel, or oven mitts, remove the loaves to a cooling rack, and let them stand for at least 20 minutes before eating. Repeat the baking method with the second two loaves. These loaves are best eaten within four hours. If you do not eat all the bread, the loaves can be frozen in a plastic bag. When you're ready to eat a loaf, remove it from the freezer until it defrosts and bake it for 5 minutes in a 400 degrees F (205 degrees C) oven to crisp up the crust. Once reheated, it will go stale relatively quickly.
"In Search of the Perfect Loaf: A Home Baker's Odyssey" by Samuel Fromartz © Viking 2014. Provided courtesy of Samuel Fromartz. All rights reserved.