For the pre-ferment
8 oz. whole-wheat flour
11 oz. water (at 75 degrees)
¼ tsp. instant yeast
16 oz. unbleached white flour
10 oz. water (at 75 degrees)
¼ tsp. instant yeast
½ oz. sea salt
• First, make the pre-ferment: Combine the whole-wheat flour, 11 ounces of water and ¼ teaspoon of instant yeast. Mix with a wooden spoon until well incorporated. Let rest on a counter covered loosely with plastic wrap for 3 hours, then place in the refrigerator for 9 to 15 hours.
• The next day, combine the pre-ferment in a large bowl with the unbleached white flour, 10 ounces of warm water, ¼ teaspoon of instant yeast and the sea salt. Mix all of the ingredients with a wooden spoon until well incorporated. The dough will be shaggy; the surface will not be smooth and some dry flour will still be visible.
• Turn and fold the dough a couple of times every 30 minutes for 3 hours. After the final turn and fold, let the dough rest for another 30 minutes.
• Divide the dough into 2 equal portions, and gently form each into a round. Let rest on a well-floured cutting board or work surface for another 30 minutes.
• To shape, flip 1 rounded piece of dough and gently flatten it into a rectangle. Very gently roll up the rectangle of dough widthwise, being careful not to destroy all of your beautiful fermentation. Repeat with the remaining dough round.
• Place both of the loaves seam-side-up on a well-floured kitchen towel or cloth, using a bit of the towel to separate the 2 loaves. Let the dough proof for 1½ to 2 hours.
• Preheat the oven to 460 degrees. Ten minutes before baking, place a baking stone in the oven. Place a rimmed baking sheet on the bottom rack of the oven.
• Using a sharp knife or scoring tool held at a 45-degree angle from the side of the loaf, make a ½-inch deep cut that runs lengthwise down the center of the loaf, leaving 1 inch at each end of the loaf untouched. Repeat with the remaining loaf.
• Place the loaves atop the preheated baking stone. Immediately place 10 to 12 ice cubes directly on the preheated sheet pan. Close the oven and don’t open it for at least 15 minutes. Bake for 30 to 40 minutes, or until the loaves are golden and sound hollow when tapped on the bottom.