Universal, ancient. Sourdough fermentation is the oldest form of bread leavening — every pre-commercial yeast bread culture used wild fermentation. The San Francisco sourdough (associated with the Gold Rush, where the specific local Lactobacillus sanfranciscensis developed) became the internationally recognised standard for the American sourdough tradition.
Sourdough bread — a naturally leavened loaf using wild yeast and lactobacillus fermentation — is the pinnacle of home bread baking. The sourdough starter (equal parts flour and water, colonised by wild yeasts and lactobacillus bacteria) is the living, maintained culture that leavens the bread and produces the characteristic sour, complex flavour. A properly made sourdough has an open, irregular crumb, a shattering crust, and a tangy, complex flavour that develops over 8-24 hours of fermentation.
The bread is the context — sourdough is the vehicle for everything that accompanies it. Excellent cultured butter, the best charcuterie, aged hard cheese, or simply torn alongside a bowl of good soup. A glass of natural wine (pét-nat or orange wine) alongside fresh sourdough is the contemporary wine-bar pairing.
{"The starter: maintained by regular feeding (discarding 80% and adding equal weights of flour and water). A healthy, active starter doubles in volume within 4-8 hours of feeding and has a domed surface. Use at peak activity","Autolyse: mix flour and water (no starter, no salt) and rest for 30-60 minutes. The flour fully hydrates and gluten begins forming passively — this produces a stronger dough with less kneading","The fold-and-stretch method: during the bulk fermentation (4-6 hours at room temperature), perform a series of stretch-and-folds every 30 minutes for the first 2 hours. This builds gluten without heat","Shaping: a tight surface tension is critical. Shape the loaf by folding the dough on itself, creating a tight ball that holds its shape during the final proof","Cold retard: after shaping, place in a floured banneton and refrigerate for 8-16 hours. The cold slows fermentation, deepens flavour, and firms the dough for scoring","Bake in a Dutch oven: preheated to 250C. The covered Dutch oven traps steam from the dough, which keeps the crust flexible during oven spring. Remove the lid at 20 minutes for the final crust development"}
The moment where sourdough bread lives or dies is the bulk fermentation endpoint — the dough should be 50-75% larger in volume, with bubbles visible at the surface and sides of the container, and should feel light and airy when gently touched (not dense and heavy as when it started). Under-fermented dough produces a dense loaf; over-fermented dough loses structure and cannot be shaped. The windowpane test (stretch a piece of dough thin enough to see light through without tearing) confirms sufficient gluten development.
{"Using inactive starter: if the starter does not pass the float test (a teaspoon of starter floats in water), it is not ready — wait","Not scoring before baking: the loaf must be scored with a sharp blade or lame — without scoring, the crust bursts unpredictably","Opening the Dutch oven too early: the steam is what allows oven spring — opening before 20 minutes collapses the rise"}