Guide · cold fermentation & biga
Cold fermentation yeast: why your fridge doesn't stop the dough
Most dough calculators treat the fridge like a switch: put the dough at 4°C and fermentation slows down instantly. In reality the dough core takes hours to cool, and during those hours the yeast keeps working almost as if it were on the counter.
1. The fridge doesn't stop fermentation right away
A dough ball or tub cools from the outside in. The bigger the mass and the more the container insulates, the longer the center stays warm. Here is how many hours the core stays above 8°C according to the simulator, with the same recipe (dough at 21.5°C, 17 hours in a 4°C fridge):
| Dough | Container | Hours above 8°C | Yeast: classic calculator | Yeast: with cooling time |
|---|---|---|---|---|
| 0.5 kg | PP Plastic Box | 1.6 h | 2.64 g | 2.70 g |
| 1.0 kg | PP Plastic Box | 2.6 h | 5.29 g | 5.16 g |
| 3.0 kg | PP Plastic Box | 5.3 h | 15.86 g | 13.69 g |
| 3.0 kg | Thick Sealed | 8.0 h | 15.86 g | 12.83 g |
For a small dough ball the difference is negligible. With 3 kg in an insulated tub, a classic calculator has you add far more yeast than needed and the dough reaches the oven overproofed.
Open this case in the simulator →2. Room temperature first, then the fridge: how to think about it
- Hours at room temperature weigh much more than hours in the fridge: even one extra hour before the fridge changes the result.
- The first hours in the fridge aren't "cold hours": the dough core takes time to drop, especially in a large batch.
- Balling before the fridge cools the dough much faster than one big mass.
- The container matters: steel sheds heat faster than plastic, a thick or sealed container holds it.
3. Biga at home temperatures
If your kitchen isn't at 18°C, the biga matures faster and needs less yeast. This is the fresh yeast dose for the biga that brings the final dough to 100% rise at bake time, with the biga at 50% of the flour, 48% hydration and 16 hours of maturation (1 kg of dough):
| Biga temperature | Yeast (% of flour) | Yeast (grams) |
|---|---|---|
| 16°C | 0.93% | 5.27 g |
| 18°C | 0.90% | 5.14 g |
| 20°C | 0.88% | 5.00 g |
| 22°C | 0.85% | 4.84 g |
| 24°C | 0.82% | 4.68 g |
| 26°C | 0.76% | 4.33 g |
The simulator also tells you how warm the refresh water should be to finish the dough at 24°C.
Try your biga in the simulator →These numbers are estimates
They come from a simplified physical model (cooling, yeast and gluten activity as a function of temperature), not from lab measurements. If you have a probe thermometer and want to compare the model with your own dough, your data is very welcome.
Calculate your dough →