Feed levain at 1:1:1 — about 55 g each. Let peak at room temperature, about 4-5 hours.

Mixer: 1 hour before levain peaks combine 450 g flour and 270 g cold water in mixer bowl. Mix until no dry flour remains. Cover and rest 1 hour. Refrigerate if kitchen is warm.

No mixer: Combine 450 g flour and 305 g water in a bowl. Mix with spatula until no dry spots. Cover and rest 1 hour.

Mixer: Add 135 g levain and 9 g salt. Mix on low 5 minutes. Increase to medium 2 minutes. Stream in 45 g bassinage water over 2 minutes on medium. Mix until smooth with a thin translucent windowpane and dough temp 75°F.

No mixer: Add 135 g levain, 9 g salt, and 10 g water. Dimple and squeeze until combined. Rubaud method for 6-8 minutes. Rest 20 minutes. Rubaud another 5 minutes. Rest 30 minutes. Stretch and folds. Rest 30 minutes. Stretch and folds.

Transfer to rectangular container. Mixer: stretch and folds at 1.5 hours, flip smooth side up, flatten. Both methods: room temp (75 f) bulk 3 to 3.5 hours total until about 20% rise with visible bubbles but no dramatic rise. Transfer to 38°F fridge for 15-17 hours.

Remove from fridge and rest at room temp 30 minutes. Flour top and flip onto work surface. Press gently to flatten. Divide into 3 even rectangles with clean cuts. Letter fold each piece and seal seam with ball of hand into a batard shape. Cover and rest 30 minutes. Preheat oven to 500°F now.

Flip each piece bottom side up. Press gently to flatten and elongate. Fold top edge down ⅔ of the way and press palm evenly across. Rotate 180 degrees and repeat. Fold in half with thumb pushing center inward and seal seam with heel of hand. Roll from center outward to taper ends. Transfer seam side down to floured couche. Support sides with couche walls. Cover and proof about 1 hour until poke test shows slow spring back with a light fingerprint.

Transfer to flipping board then seam side down onto parchment on peel. Place in fridge for 15 min for easier scoring.

Score at 45 degrees down the length of each baguette.

Conventional oven: Slide in and immediately pour ¾ cup boiling water over lava rocks or cast iron. Bake at 485°F for 10 minutes with steam. Open door briefly to release steam. Reduce to 450°F and bake 10 more minutes until browned.

Convection oven: Load bread and add boiling water to rocks. Turn oven off for 8 minutes with steam. Open door briefly to release steam. Turn oven back on to 485°F and bake 10 more minutes until browned.

Cool on wire rack 20-30 minutes before cutting. Listen for the crackling!