Sourdough with a real bottom crust
A loaf baked on a tray rises slowly and ends up with a pale, soft bottom, because a thin tray gives the dough almost no heat from below. A preheated steel plate gives it a burst of heat the moment it lands, which is what drives the oven spring that opens the score and sets a crisp, dark base. Add steam for the first twenty minutes and you have a bakery loaf without a Dutch oven.
The dough
One loaf. You need an active starter: fed four to eight hours before, bubbly and roughly doubled.
- 450g bread flour
- 50g wholewheat flour
- 360g water
- 100g active starter
- 10g salt
Mixing, folding, shaping
Mix the flours and 340g of the water and leave for 45 minutes. Add the starter, then the salt with the last 20g of water, and squeeze it through until it comes together.
Over the next two hours, give it four sets of stretch and folds, thirty minutes apart. Then leave it covered until it has grown by about half and looks domed and airy, usually three to five hours in total depending on how warm your kitchen is.
Shape into a tight round, put it seam side up in a floured bowl or basket, cover, and refrigerate overnight. The cold rest builds flavour and makes the loaf far easier to score.
Preheat and steam
Plate on the lower-middle rack this time, so the loaf has room to rise. Put an empty metal tray on the rack below. Heat the oven to 250°C and give the plate its full 45 minutes.
Turn the cold dough out onto baking paper, score it with one confident cut about 1cm deep, and slide it, paper and all, onto the plate. Pour a cup of boiling water into the empty tray and shut the door straight away.
Bake
Twenty minutes with the steam, then take the water tray out, pull the paper from under the loaf, and turn the oven down to 230°C. Bake another 20 to 25 minutes, until the crust is a deep brown and the base sounds hollow when tapped.
Let it cool on a rack for at least an hour. Cutting it hot lets the steam out and leaves the crumb gummy.
Cold dough, a fully preheated plate, steam for the first twenty minutes, and an hour of patience before the knife.