Ingredients

Makes 1 loaf (~900g)

  • 450g bread flour
  • 50g whole wheat flour
  • 350g water, room temperature (70% hydration)
  • 10g fine sea salt
  • 100g active sourdough starter (100% hydration, fed 4–8 hours prior)

Method

Day 1 — Mix and bulk fermentation

  1. Combine flours in a large bowl. Add 325g of the water (reserve 25g) and mix until no dry flour remains. Cover and rest 30–45 minutes.
  2. Mix starter with the reserved 25g water in a small bowl, then add to the dough. Incorporate by folding and squeezing until fully combined. Add salt and work it in the same way. The dough will feel slightly tacky.
  3. Perform 4 sets of stretch-and-folds over 2 hours, every 30 minutes: wet your hand, grab one side of the dough, stretch up, fold over the center, rotate 90° and repeat 4 times per set.
  4. After the last fold, cover the bowl and allow bulk fermentation at room temperature (24–26°C / 75–78°F) until the dough has grown 50–75% in volume and has visible bubbles on the surface and sides. This typically takes 4–6 hours depending on room temperature and starter strength.

Shape

  1. Gently turn the dough onto an unfloured work surface. Fold the edges toward the center to build tension, then flip the dough seam-side down. Using both hands, drag the dough toward you with cupped palms to tighten the surface. Repeat 2–3 times until the dough is a taut round ball.
  2. Rest uncovered for 20–30 minutes (bench rest).
  3. Final shape: flip the dough seam-side up. Fold the bottom third up, left side in, right side in, then roll tightly toward you. Pinch the seam. Place seam-side up in a well-floured banneton (or a bowl lined with a floured cloth).

Cold proof

  1. Cover with plastic wrap or a shower cap and refrigerate 12–16 hours (overnight). Cold proofing slows fermentation, develops flavor, and makes the dough easier to score.

Bake

  1. Place a Dutch oven (at least 5-quart / 4.7L) in the oven and preheat to 260°C / 500°F for 45–60 minutes.
  2. Cut a sheet of parchment to fit your Dutch oven. Tip the cold dough seam-side down onto the parchment.
  3. Score the top with a lame or sharp razor blade at a 30–45° angle, one decisive slash about 1cm deep. Do not saw back and forth.
  4. Lift the dough by the parchment into the hot Dutch oven. Cover with the lid and bake 20 minutes (the steam trapped inside creates an open crumb and thin crust).
  5. Remove the lid, reduce oven to 230°C / 450°F, and continue baking 20–25 minutes until the crust is deep mahogany and the internal temperature reads 96–99°C / 205–210°F.
  6. Transfer to a wire rack and cool at least 1 hour before cutting. The crumb continues to set as it cools — cutting too early produces a gummy interior.

Notes

  • Starter readiness: Use starter that has roughly doubled after feeding and passes the float test (a teaspoon dropped in water floats). An underactive starter means weak oven spring.
  • Bulk fermentation endpoint: Look for bubbles on the surface and sides, a slightly domed top, and a jiggle in the center when you shake the bowl. Temperature matters — at 24°C it takes ~5 hours; at 21°C it can take 7–8 hours.
  • Dutch oven: Creates the steam environment a deck oven provides in a bakery. A combo cooker (Lodge or similar) also works. No Dutch oven — place a tray of boiling water on the lower rack for the first 20 minutes and bake the loaf directly on a preheated steel or stone.
  • Troubleshooting dense crumb: Most likely cause is under-fermented bulk or inactive starter. Extend bulk until you see clear volume gain and bubble activity.