DIRECTIONS

• Stir the water and yeast together in a large bowl until the yeast is dissolved. Stirring in one direction with a wooden spoon, add the bread flour and stir 100 times, about 1 minute.
• Cover the bowl with plastic wrap and allow the sponge to rest at room temperature for 24 hours, during which time it will develop a pleasantly-and characteristically-sour flavor.
• The next day, you'll find that the sponge is bubbly and the extra water will have separated from it. Fold and stir the water back into the batter before continuing.
• Using a wooden spoon and always stirring in one direction, stir in the barley flour. Stir in the salt. Gradually add the 4 cups bread flour, stirring and folding the flour into the dough until it becomes too stiff to stir. Turn the dough out onto a lightly floured work surface and knead it for 8 to 10 minutes, or until it is smooth and elastic.
• Wipe the bowl clean and return the dough to it; cover with plastic wrap and let the dough rise at room temperature for 3 hours, or until it almost doubles in bulk.
• Use your fingertips to pull the dough away from the sides of the bowl and turn it out onto a lightly floured work surface, then cut the dough into 8 pieces and shape each into a ball. Lightly flour the palm of one hand and use it to gently flatten each ball. Cover the balls with a towel and let them rest for 10 minutes.
• Meanwhile, position an oven rack or the broiler rack 4 to 6 inches from the broiler element and turn on the broiler. Lightly oil a large (about 12-inch diameter) skillet that can be used under the broiler and set it over medium heat. Place a large shallow bowl or pan containing at least an inch of water near your work surface.
• Roll a ball of dough into a 9- to 10-inch round that is less than 1/4 inch thick. Lift the round and put it into the bowl of water, pressing it down gently to immerse it. Transfer the dough to a work surface and use your fingertips to create deep, rounded indentations all over the dough. Place the dough in the hot skillet (it will sizzle and steam) and cook for about 31/2 minutes, or until the bottom surface firms. (As the bread begins to cook, it may lose some of its indentations-press in some more while it is in the skillet.) Sprinkle a little more water over the bread and lift it from the skillet to the oven rack. Broil for 41/2 to 5 minutes, or until golden.
• Remove the bread from the oven and wrap immediately in a cotton cloth to preserve the bread's warmth and suppleness. Continue with the remaining balls of dough. When you've done several batches of this bread, you may be able to work out a rhythm that will allow you to roll out a bread or cook a bread in the skillet while another bread is baking under the broiler-it takes practice. You'll know you're proficient when you can work with two skillets.
• These breads should be eaten the day they are made.