Cold fermentation means making pizza dough a day or more ahead and letting it rest in the fridge. It is a common way home pizza makers get a dough that stretches easily, browns well and tastes of more than flour. The question is how long, and how much yeast that length needs.
The short version: 24, 48 and 72 hours all work. Longer times change flavor and texture more than they change whether the pizza works, and each length needs its own, smaller amount of yeast. The numbers below come from the fermentation model in our pizza dough calculator. They are predictions from a model fitted to the yeast tables pizza makers use, not measurements, and they come with ranges.
What happens in the fridge
At a typical fridge temperature of about 4 °C, baker's yeast still works, but at roughly a sixteenth of its pace at 24 °C. Gas builds up slowly, while enzymes in the flour keep breaking starch into sugars and proteins into smaller pieces. The slow rise gives the dough time to develop flavor and makes the gluten more relaxed, so a ball that has rested for two days usually stretches thinner without springing back than one mixed the same morning.
What the cold does not do is stop the clock. A dough with too much yeast for its plan will overproof in the fridge just as it would on the counter, only more slowly. That is why the yeast amount has to match the length.
How much yeast for 24, 48 and 72 hours
A typical cold-ferment plan has three parts: about an hour at room temperature after mixing, the balls in the fridge, and about two hours at room temperature before baking. With a 22 °C kitchen and a fridge at 4 °C, the model predicts:
| Time in the fridge | Instant yeast, % of flour | Model range | For 600 g of flour |
|---|---|---|---|
| 24 hours | about 0.20% | 0.12–0.34% | about 1.2 g |
| 48 hours | about 0.13% | 0.07–0.22% | about 0.8 g |
| 72 hours | about 0.09% | 0.05–0.16% | about 0.5 g |
For fresh yeast, multiply by three; for active dry yeast, multiply the instant amount by about 1.2 (the calculator uses 1 g fresh = 0.33 g instant = 0.4 g active dry; published conversions vary).
These are small amounts, too small to weigh accurately on a kitchen scale that reads in whole grams. Either use a scale that reads to 0.01 g, or dissolve a larger amount of known weight (a whole sachet, for example) in 100 g of water, use the share you need, and take that weight off the recipe's water. The calculator works out the grams for you.
Why recipes disagree so much
If you compare published cold-ferment recipes, you will find yeast amounts several times higher than these, and some about half. Part of that is the fridge: at 6 °C the model's amounts drop to about 0.17%, 0.09% and 0.06%, and at 3 °C they rise to about 0.22%, 0.14% and 0.10%. Part is the model's range. And part is that, in practice, cold dough tolerates some time past the point where it first becomes ready, and some recipes rely on that with more yeast. The model predicts only when the balls first become ready, not how long they stay usable, so more yeast than the range means less margin and, at some point, an over-proofed, slack dough.
24, 48 or 72 hours: what changes
- 24 hours is the easiest plan to fit into a week: mix the evening before, bake the next evening. The dough is more elastic and the flavor milder than with longer rests.
- 48 hours sits in the middle. Recipe writers commonly report a more extensible dough and a crust that browns more readily, probably partly because flour enzymes free sugars faster than the slowed yeast uses them; the model does not cover this.
- 72 hours gives the most relaxed dough and the most pronounced flavor. It needs the least yeast and the coldest, steadiest fridge; in a warm fridge or with too much yeast the balls can turn slack and sticky.
Beyond about three days the gluten keeps weakening and the dough gets harder to handle. Many recipes stop at 72 hours, though some go to five days; the calculator stops at 72.
Taking the dough out
Cold balls are stiff and tear when you stretch them. Take them out about two hours before baking and leave them covered at room temperature. They are ready when they have softened, look slightly puffy and a gentle press fills back in slowly. In a cold kitchen give them longer; in a warm one keep an eye on them after the first hour. In the meantime, preheat the oven as hot as it goes, ideally 250–290 °C (480–550 °F), for 45–60 minutes with the steel or stone inside.
Plan it
The pizza dough calculator takes your fridge time, room and fridge temperatures, and the time you want to eat, and gives the grams and a schedule from mixing to baking, with a calendar file. For how temperature affects the rise in more detail, see pizza dough temperature. For the fridge with a natural starter, see sourdough vs yeast pizza dough.