Two days before baking:

1. To feed starter, take maintenance starter out of refrigerator. Place 20 grams of starter in a clean jar (what is remaining is now considered discard). Stir in 100 grams warm (116°F) water and 100 grams organic all-purpose flour. On the jar, place a marker or rubber band level with the top of the starter; loosely cover jar with plastic wrap or lid and wait 4 to 12 hours or until the starter triples in size. This creates an active starter.
2. To build the levain, place 20 grams of active starter in a clean jar; what is left is now your maintenance starter that you can put back in the fridge. Stir in 110 grams warm (116°F) water and 110 grams high-gluten bread flour. On the jar, place a marker or rubber band level with the top of the levain; loosely cover jar with plastic wrap or lid and wait 6 to 12 hours until levain has peaked (domed top) or has tripled in size.  

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Float test:

1. Take a small amount of the active levain and drop it into a glass of water.
2. If the levain floats on the water’s surface, it has trapped gas, a sign of fermentation. This means it’s likely ready for baking.
3. If the levain sinks to the bottom, it may need more time to ferment and develop before using for baking.

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Note: The float test can be a helpful indicator, but it’s not the only factor to consider when determining the readiness of your sourdough starter or levain.
It should have a tangy aroma and bubbly texture.

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The day before baking:

1. For dough, pour 230 grams levain and 640 grams warm (116°F) water into a large bowl and stir until water is milky. Add 870 grams high-gluten bread flour and 50 grams organic whole wheat flour; stir with a Dutch dough hook or wooden spoon until combined. Dough will be loose and sticky. Cover with a clean, damp kitchen towel; let rest for 45 minutes.
2. Meanwhile, in a small bowl, stir together 2 tablespoons water and 20 grams salt. Pour salt mixture onto dough and pinch it in about 8 times or until salt is incorporated. Cover the bowl with a damp kitchen towel and let rest for 15 to 30 minutes.

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Bulk rise and folds:

1. 1st fold– Stretch and fold dough. With wet hands, lift one side of dough, stretch the dough up and fold it toward the middle of the dough. Repeat four times, rotating the bowl as you stretch the dough up and toward the middle. Cover dough and let rest 45 to 60 minutes.
2. 2nd fold– Coil fold. With wet hands, reach under the dough on both sides and lift dough in the center; gently pull up, allowing the dough to unstick and fold onto itself. Rotate the bowl and repeat three more times. Cover dough and let rest for 30 to 60 minutes.
3. 3rd fold– Lamination. Turn dough out onto a clean, damp surface. From the center, gently stretch and pull the dough into a large rectangle, taking time to prevent the dough from tearing. Fold dough into thirds. Starting at the short end, roll dough into a ball. Place dough back into the bowl; cover and let rest for 30 to 60 minutes.
4. 4th fold–Coil fold. With wet hands, reach under the dough on both sides and lift dough in the center; gently pull up, allowing the dough to unstick and fold onto itself. Rotate the bowl and repeat three more times. Cover dough and let rest for 30 to 60 minutes.
5. Preshaping– Turn dough out onto a surface lightly dusted with rice flour. With a bench scraper, divide dough into two equal portions. Carefully shape each one into a round by dragging your hands on the work surface and tucking the dough under itself; you want to build tension as you shape. Rest the dough, uncovered, on the counter, for 15 to 20 minutes.
6. Meanwhile, dust proofing baskets, or bannetons, slightly and evenly with white rice flour.  
7. Final Shaping– Once dough has rested, using the bench scraper, flip over the dough so it sits seam side up. This will be the bottom of your loaf. Gently stretch out the dough into a small oval. Fold the left side back toward the middle. Fold the right side toward the middle. Fold the top down, then roll up the dough. Pull the dough toward you, building tension. Once each loaf is round and taut, place it seam side up in a prepared proofing basket, or banneton. Let dough rest, uncovered, for 10 to 15 minutes.
8. Stitch the dough, taking pieces and pulling them into the middle of the dough. Cover dough with proofing basket liner or clean tea towel. Place dough in the refrigerator to cold-proof for 12 to 48 hours. Dough will not rise.

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Baking day:

1. Place a Dutch oven with lid on an oven rack in the bottom third of the oven; preheat oven to 500°F for 30 to 60 minutes.
2. Once oven is preheated, remove one proofing basket from the refrigerator. Uncover dough and dust it with rice flour. Flip dough out onto a silicone bread sling or parchment paper. Heavily dust top of dough with rice flour.  
3. Use a bread lame to score dough. Starting at a top side, score dough in a crescent shape, about ¼ inch deep and at a 45-degree angle, ending near the bottom of loaf.
4. Reduce oven temperature to 480°F. Carefully remove lid and place dough in the Dutch oven. Cover and bake for 25 minutes.
5. Remove lid and continue baking for 10 minutes.
6. Reduce temperature to 450°F. Remove bread from Dutch oven and bake directly on oven rack for 5 to 10 minutes or until bread reaches desired color.
7. Remove from oven, cool completely, 3 to 4 hours. Repeat with other loaf.