Mix all the ingredients for leaven/ levain and set aside for about 6 hours.
In another bowl all-purpose flour, bread flour, whole wheat flour and water( set aside 15g water) and mix well and 1 hour
For Bread dough
When leaven is ready mix with flour mix and set aside for 30 minutes
First 2 hours of dough mixing you need to stretch and fold (check the video for details) the dough for every 30 minutes interval.
First fold 30 minutes, after mixing you can incorporate salt too at this stage
Add rest of water and salt and combine well.
Second fold 60 minutes after mixing
3rd fold after 90 minutes of mixing
4th fold after 120 minutes of mixing
5th fold after 3 hours of mixing
6th fold after 4 hours of mixing
7th fold after 5 hours of mixing
8th and final fold are after 5.30 hours of mixing
Each set consists of 4 folds, one at the North, South, East and West sides. Wet your hands with a little water to prevent sticking and then lift one side (North) of the dough with two hands. Stretch the dough up high enough just so that you can fold it completely over to the other side of the dough in the bowl. Rotate the bowl 180° and do the other side (South). Finish the other two sides (East and West) to complete the set. Let the dough rest 30 minutes, covered, between sets.
At the end of the bulk fermentation your dough should have risen between 20% and 50%, and should show some bubbles on top. The sides and the edge of the dough where it meets the bowl should be slightly domed showing strength.
In a workspace if you want you can dust lightly with flour, I usually skip this step. Transfer the dough from the bowl lightly pulling the dough towards you. This gentle turning and pulling motion will develop tension on the top of the dough forming a round circle. Let the dough rest for 25 minutes, uncovered.
Shape the dough
In a lightly floured workspace, lightly spread the dough. Then, grab the left and right sides of the dough and stretch them away from each other, fold one side over toward the other and repeat with the other side. You’ll now have a tight package that resembles a letter.
Finally, flip, or roll down the dough so the seams are all on the bottom and using two hands cup the top part of the round and drag the dough gently towards your body. The angle of your hands will gently press the bottom of the dough on the counter creating tension, forming a skin on the top of the dough as you drag.
After shaping, let the dough rest on the bench for a few minutes and then place seam-side-up into a towel-lined kitchen bowl or banneton that was lightly dusted with rice flour and all-purpose flour.
Once you shaped the dough transfer to banneton and set aside refrigerator for cold ferment for 12 hours.
Preheat oven for 1 hour at 500°F (250°C). You can pre-heat the oven with Dutch oven or combo cooker inside. If you don’t have Dutch oven, place the dough in the baking sheet lined with parchment paper. You need to keep some ice cubes to create steam.
Bake the bread at 500°F (250°C) for 25 minutes with lid and then reduce the temperature and remove the lid and bake 450°F (230°C) for 20 minutes or until its golden-brown color.
Wait 1-2 hours before slicing the bread (I know, it’s hard to do this) to ensure the interior is set otherwise you will get gummy bread.