15g starter

120g cool water

105g whole wheat flour

Then

240g water

175 g bread flour

200 g whole wheat flour

12 g salt

Make the pre-ferment. Measure and mix together 15 grams of starter, 120 grams of water, and 105 grams of whole wheat flour. Cover and let ferment in a cool place overnight or around 12 hours.

Then, make the dough.

Mix all the pre-ferment with the 240 grams of water until well dispersed.

Mix with that the remaining flour and salt. Mix until combined but don’t worry too much about kneading at this point.

For the next 2 hours, every 30 minutes, give the dough series of stretch-and-folds: dip your hand in water, grab the bottom of the dough, fold it over the top. Turn the bowl about 30 degrees and repeat 6 times.

After the two hours, cover and let rise most of the day until doubled in size.

Shape the dough: gently turn it out of the bowl, being careful not to over-deflate it. Fold it over and stretch, building tension in the top of the dough several times – without deflating the dough, best you can.

Place in a well-floured banetton with a liner and proof overnight in the fridge.

Put a dutch oven or combo cooker in the oven and 450 degrees for at least 30 minutes.

Carefully turn the bread out into the base of the combo cooker and slash the top deeply. (I like a + most)

Cover and bake for 40 minutes, then carefully remove the top (you will get a steam burn) and bake for 10 more minutes to get a really nice brown crust.