Mix all ingredients thoroughly. Make sure that all flour is hydrated. Cover the dough with cling film and let it ferment for 8 hours at a temperature of 72ºF / 22ºC.

Mix water and flour with the levain and let the dough rest for an hour.

Add salt and perform one stretch and fold session. Let the dough rest for 30 minutes and perform another stretch and fold session.

Make a windowpane test and check if more stretch and folds are required. Otherwise, let the dough rest during the rest of the bulk fermentation. Total time for bulk fermentation for these baguettes was 4 1/2 hours at a temperature of 75ºF / 24ºC. You may have to adjust the time due to the strength of your starter and ambient temperature, etc.

Lightly flour your work surface and dump out the dough. Divide it into three pieces with your bench knife. Flatten the dough gently with your hands. Fold one side against the other and repeat with the other. Form the dough to a baguette by rolling it gently against the work surface. There's a link to an excellent video showing how to form a baguette in the recipe notes.

Preheat your oven to 480ºF / 250ºC.

Let the baguettes ferment until they pass the finger poke test. Total time for the final fermentation for my baguettes was 1 hour and 15 minutes at a temperature of 75ºF / 24ºC.

Score each loaf 3 or 4 times and place them in the oven. Add a lot of stem with your preferred technique. Bake the baguettes for 30- 40 minutes. Open the oven lid after 15-20 minutes and ventilate out the steam. You may also lower the temperature if necessary.

Let the baguettes cool on wire racks.