Step 1

Stir together 2 1/4 cups 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. When dough becomes too stiff to stir with spoon, knead dough in bowl to form a ball. Turn dough onto a clean work surface, and knead until there are no dry patches of flour, about 1 minute. (Dough will be sticky. To easily clean doughy hands, sprinkle hands lightly with flour, and rub together over a trash can to loosen any stuck dough.) Place dough in a clean large bowl, and drizzle with oil. Knead dough in bowl until oil is incorporated, about 1 minute. Cover bowl tightly with plastic wrap, and let rest at room temperature until dough begins to rise, about 1 hour.

Step 2

Uncover dough; starting at edge of bowl farthest from body, use a wet hand to lift edge of dough and stretch until there is tension, approximately 1 foot in the air. Press the dough in toward the center; rotate bowl 90 degrees, and repeat motion to fold dough 4 times total. Flip dough seam side down; cover tightly with plastic wrap, and let stand 1 hour. Repeat folding process 1 more time.

Step 3

Cover dough bowl tightly with plastic wrap, and let stand at room temperature until tripled in volume, about 12 hours, or refrigerate until increased in volume 2 1/2 to 3 times, at least 24 hours or up to 48 hours.

Step 4

Line a large rimmed baking sheet with plastic wrap, leaving about 3 inches of overhang on all sides; lightly grease plastic wrap with oil. Alternatively, lightly grease insides of 6 lidded plastic pint containers with oil. Set aside.

Step 5

Uncover dough, and gently press to release air bubbles. Turn dough out onto a heavily floured work surface. Divide dough evenly into 6 portions (about 9 ounces or 255 grams each). Working with 1 dough piece at a time, stretch and fold 4 corners of dough in toward center. Flip dough seam side down. Using a bench scraper and a lightly floured hand, drag dough across work surface, rotating dough gradually with your hand as you pull it with bench scraper, until dough forms a taut ball. Using bench scraper, transfer dough ball, seam side down, to prepared baking sheet (or to 1 prepared pint container). Repeat process with remaining 5 dough pieces, spacing evenly apart on baking sheet, and pulling plastic wrap up between dough balls to prevent sticking (or place in 6 oiled plastic pint containers). Cover tightly with plastic wrap or lids.

Step 6

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