Feed starter at 1:2:2 ratios using warm (about 80 °F) water.

In a large bowl, mix 800g Bread Flour, 80g Whole Wheat Flour, and 540g Water (but not the starter) by hand until almost no dry bits remain.

Cover and let rest until the next step.

Add 170g Starter on top of the dough and mix by hand until the starter is completely integrated, about 5 minutes.

Cover and let rest for about 30 minutes.

Lightly wet the counter with some water.

Transfer the dough from the bowl onto the wet counter.

Being careful not to tear the gluten strands, spread the dough out into a rough rectangle.

Sprinkle the 17g Salt evenly over the dough.

With wet hands, knead the salt into the dough for about 5 minutes. Continue to moisten the counter as needed so that the dough doesn’t stick so much that it’s tearing.

Return the dough to the bowl and cover.

With wet hands, perform a stretch & fold by gently pulling each corner of the dough out and returning it to the center.

Perform stretch & fold #2.

Perform stretch & fold #3.

Perform stretch & fold #4.

Cover and let rest for the remainder of the bulk rise.

Lightly flour the counter and gently invert the dough onto it.

If baking more than one loaf, divide the dough into equal pieces using a bench scraper.

Shape each piece into a rough round.

Cover and let rest for about 10 minutes.

After resting, shape each piece into a boule.

Lightly line proofing baskets with flour.

Transfer the dough to the proofing baskets with the seam side facing up.

Let rest on the counter for about 20 minutes.

Move into a cold fridge for up to 16 hours.

An hour before baking, place a Dutch oven or similar pot into the oven.

Preheat oven to 500 °F

Remove the baskets from the refrigerator.

Carefully invert the dough from its basket onto a sheet of parchment paper.

Dust the top of the dough with flour.

Score the top of the dough using a bread lame or sharp knife.

Carefully remove the pot from the oven and remove the lid.

Using the edges of the parchment paper, carefully lift and move the dough into the pot.

With a mitted hand, put the lid back on the pot.

Carefully place the pot in the oven.

Reduce the oven temp to 475 °F.

Bake with the lid on for 20 minutes.

Remove the lid, reduce to 425 °F, and bake for another 25 minutes or until score edges just start to burn.

Place the bread on a wire rack and let cool for at least 45 minutes.