Bulk fermentation is done when your dough has risen enough, feels airy and jiggly, and shows good gluten strength, before it gets weak, sticky, and collapses.

What “done” bulk fermentation looks like

Use a mix of visual, tactile, and timing cues rather than just the clock.

  • Dough volume has increased by roughly 30–100% depending on temperature and recipe; many “warm” methods look for about 30–50% rise, while cooler methods may go closer to doubling.
  • Surface looks smoother and slightly domed, with a few small bubbles along the sides and top, not flat or tearing.
  • When you gently shake the container, the dough has a soft, jelly-like wobble instead of feeling dense and stiff.
  • The dough feels airy and lighter when lifted with a hand or scraper, and stretches without tearing immediately.

In practical home baking, for a typical sourdough at 23–25°C/74–78°F, this often lands around 2–5 hours, but can be shorter in hot kitchens and much longer in cool ones.

Structural and gluten checks

Bakers also rely on gluten development tests as a safety net.

  • A gentle windowpane test (stretching a small piece very thin without tearing) suggests minimum gluten development has been met and bulk may be done, provided the dough has also risen appropriately.
  • The dough pulls away from the sides of the bowl more cleanly and holds its shape better between stretch-and-folds or coil folds.
  • During the later folds, you may notice less dramatic tightening because fermentation is well underway and the gluten has already strengthened.

Think of it as a balance: enough structure to trap gas and hold shape, but not so much fermentation that the gluten starts to break down and feel slack or gluey.

Start and end points in modern sourdough talk

There’s some debate in forums and blogs, but most serious sourdough guides now frame bulk like this:

  • Bulk starts when the starter/levain is mixed into the dough (flour + water), even if you continue doing stretch-and-folds or “fermentolyse.”
  • Bulk ends when you divide and pre‑shape, or—if you’re making a single loaf—when you first shape the dough.

This matters because on warm days, a lot of fermentation happens while you’re still folding and “waiting,” so the official “bulk time” in a recipe can be misleading if you only count from the last fold.

Signs you went too far (over‑bulk)

Learning the “too late” signs helps you adjust next time.

  • Dough more than doubled at warm temps (around or above 24–25°C), then starts to slump and lose its domed top.
  • Texture turns very slack and sticky, tears when you try to pre‑shape, and struggles to hold surface tension.
  • Baked loaf has a very flat profile, weak ears, and a gummy or overly tight crumb despite long fermentation.

If you see these, shorten bulk next time—especially if you keep the dough warm or follow a method with long cold retard afterward, because fermentation continues during pre‑shape, bench rest, shaping, and the early hours in the fridge.

Quick rule-of-thumb you can rely on

When in doubt, aim for this simple combination for typical sourdough in the mid‑20s °C:

  1. Around 30–50% rise in a straight‑sided container.
  1. Smooth, slightly domed surface with visible bubbles at the edges.
  1. Light, jiggly feel and a small piece that can be stretched thin (windowpane) without tearing immediately.

If those three line up, bulk fermentation is very likely done and it’s time to divide and shape.

Information gathered from public forums or data available on the internet and portrayed here.