Place ¼ cup of the warm water in a medium bowl. Crumble in the fresh yeast or sprinkle in the dry yeast. Stir and let stand in a warm place until foamy, about 10 minutes.

In a large, shallow bowl, sift 1 cup of the flour with the salt. Make a well in the center. Add the remaining ¼ cup warm water, the cold water, and the 1 tablespoon olive oil to the yeast mixture and stir gently. Pour the mixture into the well. Using a wooden spoon, gradually stir the flour into the liquid until it is absorbed. Gradually sift in 2 more cups of the flour. When the dough becomes stiff, use your hands to form the dough into a ball.

Lightly sprinkle flour on a work surface. Place the ball of dough on the floured surface and knead it while gradually sifting onto it as much of the remaining 1 cup flour as needed to form a dough that is silky and elastic, 8 to 10 minutes. Shape into a ball.

To make the dough in a food processor, place ¼ cup of the warm water in a medium bowl. Crumble in the fresh yeast or sprinkle in the dry yeast. Stir and let stand in a warm place until foamy, about 10 minutes. Meanwhile, in the bowl of a food processor, combine 3¾ cups of the flour and the salt, and pulse to mix, about 30 seconds. Add the remaining ¼ cup warm water, the cold water, and the 1 tablespoon olive oil to the yeast mixture. Stir gently and pour into the processor with the flour and salt. Engage the processor until a ball has formed, about 40 seconds. It will still be somewhat sticky at this point. Transfer the dough to a lightly floured board and knead until silky and elastic, 3 to 4 minutes, adding more flour as necessary to achieve the proper consistency. Shape into a ball.

Place the dough in a larger, clean, lightly oiled bowl. Lightly brush the surface of the dough with olive oil. Stretch plastic wrap tightly across the bowl, covering it completely, then cover the plastic wrap with a kitchen towel. Allow the dough to rise undisturbed at room temperature in a location free of drafts until doubled in bulk, 4 to 5 hours (the longer the rise, the lighter the dough). If the dough rises too quickly, punch it down and let it rise again.

If baking the loaves on baking stones or terra-cotta tiles, sprinkle a baker’s peel with cornmeal. If you have baking stones or tiles but no peel, dust a large, rimless baking sheet with cornmeal and use it for transferring the loaves to the stones or tiles. If you are not using stones or tiles, brush a large baking sheet with olive oil and sprinkle with cornmeal or semolina.

Punch down the dough in the bowl and turn it out onto a lightly floured work surface. Knead it for several minutes until it is once again elastic. Divide the dough in half and form each half into a round loaf. Place the loaves on the cornmeal- or semolina-dusted peel or baking sheet or on the oiled baking sheet. Sprinkle the tops of the loaves with bread flour, then cover with a kitchen towel. Let rise in a warm, draft-free spot until doubled in bulk, about 2 hours, or in a cool, draft-free spot overnight.

If using baking stones or terra-cotta tiles, place them on the middle rack of the oven and begin preheating the oven to 400 degrees F 40 minutes before baking, to ensure the baking surfaces are hot. If not using stones or tiles, begin preheating the oven at least 20 minutes before baking.

Place a small, shallow pan of water on the bottom of the oven. Remove the towel from the loaves. If using a baking stone or tiles, slide the loaves off the peel (or the baking sheet) directly onto the heated surface. If using a baking pan, slide it onto the middle rack. Bake the loaves until golden and cooked through, about 30 minutes. The test for doneness is to rap the loaves on the bottom. If they sound hollow, they are done. Transfer to racks to cool for at least 15 minutes before cutting.