Preparation

• Stir together warm water and levain in a large bowl until levain is mostly dissolved. Add flour and salt. Stir to form a shaggy dough. Knead in the bowl until there are no dry patches, about 1 minute. Place dough in a clean bowl, drizzle with oil, and knead until incorporated. Cover tightly with plastic wrap and let rest at room temperature for 1 hour.
• Uncover dough; use a wet hand to lift and stretch edge of dough, folding it toward the center. Rotate bowl and repeat this folding motion four times total. Flip dough seam side down, cover tightly, and let stand for 1 hour. Repeat the folding process.
• Cover and let stand at room temperature until tripled in volume, about 12 hours, or refrigerate until increased in volume 2.5 to 3 times, at least 24 hours.
• Line a baking sheet with plastic wrap and lightly grease it. Uncover dough and turn it onto a heavily floured surface. Divide into six portions. Shape each portion into a taut ball and place onto prepared sheet. Cover tightly.
• For quicker dough, let proof for 1 hour and refrigerate for at least 1 hour. For more flavor, let proof in refrigerator for at least 6 hours or up to 3 days.