Mix the active starter and warm water in a large bowl until combined.

Add the flour and mix by hand until just combined into a shaggy mass. Let this rest, covered, for 30 minutes (autolyse).

Sprinkle the salt over the dough. Dimple it in with wet fingers, then mix until the salt is incorporated.

Perform four sets of stretch and folds, spaced 30 minutes apart. For each set, wet your hands, grab one side of the dough, stretch it up, and fold it over the center. Rotate the bowl and repeat three more times.

After the final set of folds, let the dough rest, covered, at room temperature (around 72F) for 2 to 4 hours, or until it has increased in volume by about 50% and shows some bubbles.

Gently shape the dough into a tight log or oval and place it seam-side down into a lightly greased 9×5 inch loaf pan.

Cover the pan loosely and let it proof at room temperature for 1 to 2 hours, or until the dough has risen about 1 inch above the rim of the pan.

Preheat your oven to 375F (190C) with a rack in the lower third position.

Bake for 35 to 45 minutes, or until the crust is golden brown and the internal temperature reaches 200F (93C).

Remove the bread from the pan immediately and let it cool completely on a wire rack before slicing, about 2 hours.