In a large bowl, combine the active sourdough starter, filtered water, and flour. Mix until no dry spots remain. Add salt and gently work it into the dough until incorporated.

Cover and let the dough rise at room temperature until it doubles in size, usually 4–6 hours depending on the warmth of your kitchen. You can perform stretch-and-folds every 30–45 minutes for the first couple of hours to strengthen the gluten structure.

Gently turn the dough onto a floured surface.

Divide the dough into 3 equal sections.

Shape each section into a rectangle.

Fold one long side over like a letter and press with your thumbs to seal.

Roll again and seal with your thumbs, then pinch the seams tightly.

Place seam-side up on a floured tea towel on a baking sheet.

Shaping a sourdough baguette may take practice, but each time you’ll improve and achieve that classic long, slender loaf.

Cover the baguettes and refrigerate for 12–14 hours. This slow fermentation develops the flavor, enhances the crust, and makes the dough easier to handle when baking.

Preheat oven to 475°F. Place a loaf pan with tea towels or lava rocks and carefully pour in boiling water to create steam.

Lower oven to 450°F and place baguettes on a floured baking sheet or pizza steel.

Bake for 15 minutes with steam, then remove the steam source.

Rotate the pan and bake another 15–20 minutes until golden brown and crisp.