Step 1

To make the levain: Knead together the levain ingredients to make a smooth, stiff dough. Place the levain in a lightly oiled bowl, cover it, and allow it to ferment overnight at room temperature (65°F to 75°F). It should take the levain about 12 hours to mature. The mature levain will have doubled in size and be domed on top, or just beginning to sink in the middle., To make the dough: Tear the levain into small pieces and add it to the dough water. Add the remaining ingredients and mix until there are no remaining dry pockets of flour. If mixing by hand, use a dough scraper to blend the dough and break down the levain. In a stand mixer, mix the dough on the lowest speed for 2 minutes using the hook attachment., Cover the bowl and allow the dough to rest for 30 minutes., Knead the dough by hand for 3 minutes, or in a stand mixer for 1 1/2 minutes on speed

Step 2

The dough will be quite sticky., Allow the dough to rise for 60 minutes in an oiled and covered bowl., Give the dough a fold and return it to the bowl to rise for another 60 minutes., Gently deflate the dough and divide it in half. Pre-shape it into two rounds. Place the rounds seam side up on a floured surface, covered well. Let the rounds relax for 20 minutes., Shape the loaves into either a bâtard (football) shape or a round (depending on how you plan to bake it)., Cover the loaves with greased plastic wrap and allow them to rise on lightly greased parchment for approximately 2 hours. Loaves can also rise in an oiled Dutch oven or cloche; or seam side up in a well-floured brotform, or a bowl lined with a very well-floured cloth., Alternatively, refrigerate the loaves after shaping for up to 16 hours before baking., Preheat the oven to 450°F. If you’re planning to bake on a stone with steam, preheat the stone and a cast iron frying pan on the shelf below the stone for 60 minutes., Score the loaves with one long angled cut down the center of the loaf, and spray or brush them with water., When baking on a stone, slide the parchment and loaf onto the hot stone. Pour 1 1/2 cups boiling water into the cast iron frying pan. Be sure to wear good oven mitts to prevent a steam burn., If baking in a Dutch oven or cloche, remove the lid after 20 minutes and allow the loaf to finish baking in a dry oven., Bake the bread for 35 to 40 minutes. The loaves should be a rich brown, firm on the sides, and sound hollow when tapped on the bottom. Their internal temperature should be 195°F., Remove the loaves from the oven, and cool them on a rack. Store at room temperature, lightly wrapped, for a day or so; freeze for longer storage.