7:00 AM – Starter Initialization: In a clean glass jar, add the 5g of mature sourdough starter culture to 35g of room-temperature water and whisk together thoroughly until completely loose.

Flour Incorporation: Stir in the 30g of all-purpose (or bread) flour and 5g of rye flour. Mix well until no dry pockets remain, cover loosely, and let it sit at room temperature 74–78°F (23–26°C) for 8 to 10 hours until the starter reaches its peak and triples or more in volume.

5:00 PM – The Flour Hydration: In your stand mixer bowl, combine the 310g of baseline water with 405g of bread flour and 45g of fine rye flour. Mix with a heavy spoon or your hands just until a shaggy, raw dough mass forms and no dry spots remain. Cover the bowl and let it rest for 1 full hour to complete the autolyse, fully hydrating the flour and activating natural gluten development.

6:00 PM – Levain Integration: Pour 90g of your mature, peak-ripened levain directly over the autolysed dough.

Mechanical Mixing: Secure the bowl in your stand mixer fitted with the dough hook. Mix on low speed for 2 to 3 minutes (or use speed 3 on a KitchenAid mixer for 3 to 4 minutes) until the starter is completely incorporated. Cover and let the dough rest for 30 minutes.

6:30 PM – Salt and Bassinage Addition: Sprinkle the 9g of fine sea salt evenly over the dough surface and pour in the reserved 27g of extra cold water. This bassinage process adds a secondary splash of liquid to tighten the gluten network while bringing the total hydration safely to 75%.

High-Speed Emulsification: Mix on a low speed for 2 to 3 minutes (or KitchenAid speed 3 for 5 to 6 minutes) until well incorporated. The dough should pull together into a cohesive ball but remain slightly sticky on the bottom. Cover and leave to rest for 30 minutes at 74–78°F / 23–26°C.

7:00 PM – First Stretch and Fold: With wet hands, slide your fingers under one side of the dough, pull it upward gently to stretch it, and fold it over the center. Rotate the bowl 90 degrees and repeat. Perform this on all 4 sides, then cover and rest.

Progressive Structural Folds: Continue building vertical dough strength by executing regular stretch-and-folds spaced 45 minutes apart: 2nd fold at 7:45 PM, 3rd fold at 8:30 PM, and the 4th/final fold at 9:15 PM.

Final Bulk Proof: Following the final fold, let the dough proof undisturbed for 30 minutes at 76–80°F (23–26°C). Keep a close eye on the dough—look for a distinct lightness, small surface bubbles, and a 40% to 50% volume expansion. Transfer the covered container directly into the refrigerator to undergo an overnight cold fermentation retard for 9 to 14 hours.

The Next Morning – Dividing the Portions: Remove the cold, structured container from the refrigerator. Tip the dough out gently onto a lightly floured work surface. Using a bench scraper and a kitchen scale, divide the dough cleanly into 3 equal portions (approx. 250g each).

Cylinder Preshaping: Take a portion of dough and gently pat it into a rough rectangle. Fold the top third down to the center, and the bottom third up over it, like a letter. Roll it away from you into a loose cylinder. Repeat for all 3 portions, cover with a damp cloth, and let them rest on the counter for 20 minutes to relax the gluten.

The Final Baguette Shape: Dust your hands lightly with flour. Take a cylinder and flatten it slightly. Using your thumb, create a small indentation down the center length. Fold the top edge down to the center crease and seal the seam with the heel of your hand. Fold the dough completely in half away from you, trapping a core of air inside, and pinch the final long seam tightly shut. Place your hands in the center of the log and roll it back and forth against the counter, applying gentle outward pressure to extend the log into a 14 to 15-inch rope with tapered pointy ends.

The Canvas Couche Rest: Transfer each shaped baguette carefully onto a well-floured linen couche, pulling the canvas fabric upward between the logs to create a supportive wall that forces them to rise vertically rather than flattening out. Cover loosely with a towel and let proof at room temperature for 1 hour.

Preheating and Setup: One hour before baking, place your baking stone on the middle rack and an empty metal iron tray on the bottom rack, preheating the oven to a smoking hot 480°F (249°C).

The Inverted Transfer & Scoring: Using a baguette transfer board or thin cardboard, gently flip a proofed baguette off the couche so it sits seam-side down on a sheet of parchment paper. Hold your scoring lame at a sharp 45-degree angle relative to the dough surface. Make 4 to 5 swift, shallow, vertical slices down the length of the loaf. Ensure each cut overlaps the previous one by about one-third of its length; this ensures a symmetrical open expand rather than an unappealing sideways twist.

The High-Steam Stone Bake: Prepare 10 solid ice cubes. Slide the baguettes along with the parchment paper onto the scorching hot baking stone, dump the ice cubes straight into the bottom iron tray to release a massive plume of steam, and slam the oven door shut. Bake with steam at 480°F (249°C) for exactly 10 minutes.

The Crisp Uncovered Finish: Carefully open the oven door to vent any remaining steam, remove the bottom water tray, lower the temperature down to 450°F (232°C), and continue baking uncovered for an additional 15 minutes until the crust turns a deep golden-brown, crackly finish. Transfer to a wire rack and let cool completely before slicing.