Build the levain in the morning after milling fresh flour. Store somewhere warm around 78°F (25°C) ambient.

Mix flour and water (reserve 50g water for the mix, later) very well in a bowl and cover. Ensure all dry flour is hydrated. Store near levain.

Using about 30g of the reserved water, incorporate levain build into autolyse and hand-mix thoroughly. Slap and fold for 6 to 8 minutes until dough holds shape well. Place dough back into the bowl and let rest for 5 minutes. Then, use remaining water, if necessary/desired, to incorporate salt into mixture. The dough will initially break apart and then come back together. Slap and fold an additional 3 to 6 minutes until the dough starts to catch air and strength is built enough to keep dough relatively in shape on the counter.

At 80ºF bulk fermentation typically takes me somewhere between 3.5 and 4 hours. Watch the dough near the end–as I mentioned earlier, fermentation can quickly get out of control. Perform four sets of stretch and folds (each set is a stretch and fold at North, South, East & West), one every 30 minutes.

Divide the dough into two masses; each scaled at 950 grams. Lightly shape each mass into a round, cover with an inverted bowl or moist towel, and let rest for 25 minutes.

Shape each mass into a boule or batard, whatever your preference may be. Once shaped, place the dough into a banneton lightly dusted with white rice flour, or into a basket with no flour but lined with a cotton tea towel.

Retard immediately into the refrigerator at 39°F (3°C) for 12 hours.

In the morning, preheat your oven to 450°F (232°C). You can bake these loaves in a Dutch oven or combo cooker or with my method for steaming your home oven. Bake for 20 minutes at 450°F (232°C) with steam, and an additional 35 minutes without steam, until done to your liking.