How long does sourdough need to rise?

Why timing matters

Sourdough rise time isn't a single number — it's a window shaped by three forces: starter activity (the population of wild yeast + lactobacilli), dough temperature (every 10°F roughly doubles speed), and hydration (more water = faster bulk). Get any of these wrong and the dough either under-ferments (dense, gummy crumb) or over-ferments (slack, sticky, tears when shaped).

The two-phase model (canonical published method)

Most home + professional bakers follow a two-phase rise:

1. Bulk fermentation — dough rests at room temperature 4–6 hours at 75°F (24°C). During this phase, gluten develops via stretch-and-folds (3–4 sets over the first 2 hours), gas accumulates, and flavor compounds form. The dough should grow ~50% in volume + show surface bubbles + jiggle when nudged.

1. Cold proof — shaped dough rests in the fridge 12–18 hours (some bakers go 24–48 for deep flavor). Cold slows fermentation drastically without stopping it, develops more complex tang (lactic acid > acetic acid at lower temps), firms the dough for easier scoring, and produces better oven spring.

Same-day vs cold-proofed

Same-day bakes (no fridge phase) work and produce a milder flavor. But most published bakers (Forkish "Flour Water Salt Yeast", Robertson "Tartine Bread", Hamelman "Bread", King Arthur Baking) include cold proof for: (a) flavor depth from extended lactic-acid production, (b) easier handling — cold dough holds shape, (c) better oven spring — the cold dough's surface dries slightly and "tears" more dramatically when scored, producing dramatic ears. Skip the cold proof only if pressed for time.

Temperature math (the most-confused variable)

A 10°F drop roughly doubles bulk time: - 65°F kitchen: 8–10 hours bulk - 75°F kitchen (typical): 4–6 hours - 80°F kitchen: 3 hours (watch closely — over-fermentation risk rises)

Most home kitchens drift 65–75°F. If yours sits at 68°F, plan on 6–7 hours. If you preheat the oven for an unrelated task, the kitchen temp climbs — adjust mid-bulk.

The float test (definitive readiness check)

Drop a small piece of dough in room-temperature water: - Floats → ready for shaping + cold proof. Gas pockets sufficient. - Sinks → not done. Continue bulk 30 minutes, retest. - Floats then sinks slowly → borderline; shape now if cold proof is long, wait 30 min if same-day bake.

Common over/under fermentation signs

Under-fermented: dough is firm + dense; bubbles few + small. Bake yields a dense, gummy crumb with little open structure.

Over-fermented: dough is slack + sticky + falls apart when shaped. Float test fails (just disintegrates). Bake yields flat loaf with dense gummy crumb (different cause, same outcome).

Cross-reference: see /pages/what-ratio-of/water-to-flour-bread for hydration math + /pages/what-temperature-for/baking-bread for oven temp + /pages/how-long-does/pizza-dough-rise for related-but-different yeast-driven dough timing.