Bulk fermentation is one of the most important steps in baking sourdough. It’s where your dough transforms, developing strength, flavour, and the rise you’re aiming for. But how long should it actually take?
Let’s break it down.
What Happens During Bulk Fermentation?
During this stage:
- Gluten strengthens through gentle stretch and folds.
- Yeast and bacteria begin producing gas, giving your bread structure.
- Acids develop, which deepen flavour and help with shelf life.
👀 Tip: People often look for bubbles on the surface but they’re not the best indicator! Instead, pay attention to how your dough feels and rises.
How Long Does It Take?
Bulk fermentation generally takes 3 to 8 hours, depending on a few key factors:
✔ Temperature
The ideal range is 25-28°C. Colder kitchens will slow things down, while warmer ones speed things up.
✔ Starter Amount
Using a higher percentage of starter will speed up fermentation. Using less will slow it down (which is great for warmer climates).
✔ Starter Strength
If your starter isn’t bubbly and doubling within 4-6 hours of feeding, it could slow down or even stall your fermentation. Always start with a strong, active starter.
How to Tell When It’s Done
Forget the timer, your dough tells you when it’s ready.
Look for these signs:
- Dough has risen by 30-50% (30% in warmer climates, closer to 50% in cooler ones)
- Feels smooth and pillowy
- Surface is no longer sticky
- Holds its shape when gently touched
Still not sure? Check out Susan’s ‘Perfectly Proved’ guide for step-by-step visuals.
Don’t Forget Your Starter
Even perfect timing and temperature can’t make up for a weak starter.
✔ Before starting your dough, make sure your starter is:
- Bubbly and active
- Doubling in volume in 4-6 hours
- Smelling pleasantly tangy, not sharp or sluggish
Your bulk fermentation is only as good as the starter that kicks it off.
Adjusting for Your Kitchen
Every home kitchen is different but don’t worry, you can adjust:
🧊 Cold kitchen?
- Use a proofing box
- Place your dough in the oven with the light on
- Wrap your bowl in a warm tea towel
🔥 Warm kitchen (28°C+)?
- Use cooler water in your dough
- Watch closely, fermentation can move fast!
- You may want to bulk ferment to only a 30% rise, then cold-proof
Final Thoughts
Bulk fermentation isn’t an exact science, it’s a feel thing.
By learning to read your dough instead of just watching the clock, you’ll start to get consistently better bakes.