Naturally leavened sourdough bread

Weigh 500 g bread flour and 500 g of mixed wheat flours, spelt and whole wheat, to 1,000 g total.

Add 750 g room temperature water and work it through with a bench scraper and then your hands until there are no dry spots.

Add another 50 g water if it seems dry, to 800 g and 80% hydration, and mix only until hydrated.

Cover with a kitchen towel and autolyse about half an hour.

Float test the starter: a teaspoon-sized spoonful in water should float. It should be grown, very bubbly, slightly domed and about to collapse when jiggled.

Scrape 200 g starter in and pinch it through the dough with thumb and forefinger until incorporated.

Add 20 g kosher salt with 50 g water and pinch it in the same way.

Work the dough in the bowl with a lifting and turning motion, scooping down the side, lifting, shaking to stretch and pressing into the centre, for about ten to fifteen minutes, until it is smoother, less sticky, more elastic and extensible.

Cover and leave at room temperature for bulk fermentation, where the yeast feeds and produces gas.

After an hour, dampen your hands and fold: lift and stretch the dough upwards on two opposite sides and fold it onto itself, give the bowl a quarter turn and repeat, gently, to build and maintain strength.

Repeat the fold every hour, in a warm spot if the dough has cooled; three folds in total.

Dust the bread baskets generously with a 50-50 mix of white rice flour and all-purpose flour.

Flour the work surface and let the dough pull itself out of the bowl.

Divide roughly in half with a bench scraper, pressing down and twisting; do not weigh, and keep the pieces apart so they do not fuse.

Pre-shape: gather the edges into the centre into a bundle, flip it smooth side up and tuck the edges underneath with the bench scraper until tight, with only a little flour underneath so it has friction.

Cover with a clean dry towel and bench rest about 15 minutes so the gluten relaxes.

Shape a batard: flatten slightly, fold in the sides like a burrito, then roll up from the near end away, pulling back as you roll to build tension, and chop the ends in.

Put the loaf rounded side down into the dusted basket, pinching any open seams, and cover with the plastic cap.

Proof one to two hours, until settled into the basket, slightly expanded, and the poke test leaves a slight indentation that springs back slowly.

Cover and refrigerate overnight; bake from cold, which firms the dough and makes handling easier.

Preheat the oven to 500F with the bottom of the Dutch oven inside, on a low rack, for at least about 45 minutes.

Dust the bottom of the loaf with a little flour, turn it gently out onto a piece of parchment paper and lift off the basket and liner.

Slash the loaf twice with a lame held at about a 30 to 45 degree angle, quickly and confidently, to give the dough a predictable place to expand.

Lift the loaf by the parchment into the hot Dutch oven, put the lid on and return it to the oven, working quickly.

Bake with the lid on 15 to 20 minutes, split as 17, for maximum oven spring from the trapped steam.

Remove the lid to release the steam and bake about another half hour, until very dark brown but not burned.

Lift the loaf out by the parchment with tongs. Little blisters on the sides are a sign of good fermentation and it should sound hollow when tapped.

Cool completely, several hours, before slicing, so the steam is reabsorbed into the crumb rather than lost.

Slice with a bread knife or another serrated knife, which cuts a soft interior and hard crust without compressing the loaf.