At 7:00 AM, add sourdough starter to the water and whisk together.
Add the all-purpose (or bread) flour and rye flour, mix well, and cover loosely.
Let it sit at room temperature (74-78°F) for about 8-10 hours until the starter reaches its peak and triples or more in volume.
Step 2: Autolyse
At 5:00 PM, mix 207g of water with all of the flour (bread flour and semolina flour) in a bowl until no dry flour remains.
Cover the bowl and let it rest for 1 hour to complete the autolyse, which hydrates the flour and activates gluten development.
Step 3: Mix in the Starter
At 6:00 PM, add 60g of the mature sourdough starter (levain) to the autolysed dough.
Mix on low speed of a mixing machine for 2-3 minutes (or KitchenAid on speed 3 for 3-4 minutes) until well incorporated. If mixing by hand, use the Rubaud or slap-and-fold method for about 5-7 minutes.
Cover and let it rest for 30 minutes.
Step 4: Add Salt and Bassinage
At 6:30 PM, add the salt and the 30g of extra cold water (bassinage process to help tighten up gluten).
Mix on low speed for 2-3 minutes (or KitchenAid on speed 3 for 5-6 minutes) until well incorporated. The dough should come together but remain sticky on the bottom. If mixing by hand, use the Rubaud or slap-and-fold method for about 10 minutes, taking brief stops to help tighten gluten.
Cover and leave to rest for 30 minutes at 74-78°F / 23-26°C.
Step 5: Stretch and Folds (Bulk Fermentation)
At 7:00 PM, wet your hands and perform the 1st stretch and fold. Cover and rest.
At 7:45 PM, perform the 2nd stretch and fold. Cover and rest.
At 8:30 PM, perform the 3rd stretch and fold. Cover and rest.
At 9:15 PM, perform the 4th and final stretch and fold.
After the final stretch, let the dough proof for an additional 30 minutes at 76-80°F / 23-26°C. Look for bubbles on the surface, a lighter texture, and a 40%-50% rise. Keep an eye on it—if it rises too fast, shorten the time between stretches.
Step 6: Preshaping
At 9:45 PM, transfer the dough onto a work surface and dust the top with flour. Flip the dough over so the floured side faces down.
Fold the dough onto itself so the flour on the surface remains entirely on the outside of the loaf (this will become the crust).
Shape into a round and let it rest on the work surface uncovered for 30 minutes.
Step 7: Final Shaping & Cold Proof
At 10:15 PM, dust the dough with flour. Use a dough scraper to flip it over onto the work surface (floured side down).
Starting at the side closest to you, pull the right 2 corners of the dough to the left, then fold them up into half of the dough. Repeat this action on the left side.
Roll the dough tightly into a smooth, taut log/roll.
Transfer the roll, seam side up, into a prepared proofing basket (banneton or a loaf pan lined with a kitchen towel dusted with flour).
Cover it with plastic and return the dough to an 80°F (27°C) environment for 15 minutes.
Transfer the covered dough to the refrigerator for a cold fermentation lasting 14-24 hours.
Step 8: Baking
The next day, preheat your oven to 500°F (260°C) with a cast-iron Dutch oven and its lid inside for 45 minutes to 1 hour.
Remove the cold dough from the fridge and flip it over onto a sheet of parchment paper.
Score the top with a sharp knife or scoring lame.
Carefully transfer the dough into the hot cast-iron pan and cover it with the lid to trap steam.
Bake at 500°F for 15 minutes with the lid on.
Remove the lid, lower the oven temperature to 450°F (232°C), and bake for 20 more minutes until the crust is deeply golden brown.
Let cool completely on a wire rack before slicing.
-**Bassinage Process:** The addition of 30g extra cold water during the salting stage is called bassinage. This technique helps tighten the gluten network while maintaining a high overall hydration rate of 79%.-**Hand Kneading vs. Machine:** If you don't have a mixer, hand kneading using the Rubaud or slap-and-fold method will take longer (about 10 minutes total for step 4). Taking brief breaks during hand mixing helps the gluten structure self-tighten.-**Fermentation Timing:** Keep a close eye on your dough during the stretch and fold stages. If the ambient temperature is higher and the dough is rising too rapidly, shorten the rest intervals between your stretches to 40 minutes or less.-**Steam Management:** Leaving the Dutch oven lid on for the first 15 minutes of baking