Stir the bread flour and 80°F water in a large bowl until no dry flour remains, then cover and rest for 45 minutes. The dough looks rough and shaggy.

Spread the starter and salt over the dough, then squeeze and fold it with wet hands for 3 minutes. Move it to a clear, straight-sided container and mark the starting level with a rubber band. The dough looks smooth and slightly sticky, with no streaks of starter.

Every 30 minutes for 2 hours, wet your hand, lift one edge of the dough, and fold it over the center, working around all four sides. The dough turns springy and holds a rounded shape.

Keep the dough covered at 75 to 78°F until it has grown 50 to 75 percent above the rubber band, usually 4 to 6 hours after you added the starter. The top looks domed and jiggly, with bubbles along the sides.

Scrape the dough onto a lightly floured counter, fold the edges into the center, flip it seam side down, and rest it for 30 minutes. The round relaxes and spreads a little.

Rub 2 tablespoons of rice flour into a 9-inch banneton. Flip the round, fold the four edges into the center, flip it again, drag it toward you to tighten the surface, and place it seam side up in the banneton. The ball holds a firm dome without spreading.

Cover the banneton with a shower cap and refrigerate for 10 to 14 hours. The dough feels firm and slightly puffy, and a floured fingertip leaves a dent that springs back slowly.

On baking day, put the Dutch oven with its lid in the oven and heat it to 475°F for 45 minutes. The oven and pot are fully hot before the dough comes out of the fridge.

Turn the cold dough onto a 12 by 16 inch sheet of parchment, dust it with flour, and cut one 1/2 inch deep slash at a 30 degree angle with a razor blade. The cut opens cleanly without tearing.

Wearing oven mitts, lift the dough by the parchment into the hot Dutch oven, cover it, lower the oven to 450°F, and bake for 20 minutes. The loaf looks tall and pale gold, with the slash starting to open.

Remove the lid and bake 20 to 25 minutes more, until an instant-read thermometer in the center reads 205 to 210°F. The crust turns deep brown and the loaf feels light.

Lift the loaf onto a wire rack and cool it for at least 1 hour before slicing. The crust crackles as it cools, and the crumb sets from sticky to soft.