Stir together warm water and levain in a large bowl until levain is mostly dissolved. Add flour and salt. Stir using a wooden spoon to form a shaggy dough. Knead dough until there are no dry patches, about 1 minute. Place dough in a clean bowl, drizzle with oil, and knead until oil is incorporated. Cover with plastic wrap and let rest at room temperature for about 1 hour.

Uncover dough and stretch edges until there is tension. Fold dough into center, rotate bowl 90 degrees and repeat four times. Cover tightly with plastic wrap and let stand for 1 hour. Repeat folding process.

Cover bowl tightly with plastic wrap and let stand until tripled in volume, about 12 hours, or refrigerate for 24 to 48 hours.

Line a baking sheet with plastic wrap, leaving overhang and lightly greasing it. Alternatively, grease six lidded pint containers.

Uncover dough and gently press to release air. Turn out onto a floured surface and divide evenly into six portions. Stretch each portion and shape it into a taut ball. Transfer to the prepared baking sheet or containers, spacing evenly and covering tightly.

For faster dough, let proof at room temperature for 1 hour, then refrigerate for at least 1 hour or up to 5. For more flavorful dough, proof slowly in the refrigerator for at least 6 hours or up to 3 days.