Poolish & biga in pizza dough — the guide
Some of the best pizza dough starts the night before — not as dough, but as a small bowl of flour, water and a crumb of yeast left to ferment on the counter. That bowl is a preferment, and the two classics are poolish, the liquid one, and biga, the stiff one.
This guide covers what a preferment actually buys you, how the two differ, when to reach for which, and exactly how the calculator splits a recipe into a tonight bowl and a tomorrow bowl. The dose arithmetic underneath it all lives in the yeast guide.
What a preferment buys
Three things, mainly. Aroma — the prefermented share of the flour ferments long and slow, stacking up the lactic, nutty, faintly boozy notes a same-day dough never reaches. Extensibility— acids and enzymes quietly soften that flour’s gluten, so the final dough stretches further with less spring-back. Color — fermentation by-products feed the browning reactions, so the crust toasts deeper at the same oven setting.
The price is not effort but planning: one extra bowl, stirred the night before, no kneading. Time does the work, not you.
The liquid one and the stiff one
Poolish is equal weights of flour and water — 100% hydration. It bubbles like a batter, ferments fast and evenly, and pushes the dough toward silkiness: sweet-lactic aroma, easy stretch, open crumb.
Biga holds the water back — 45% hydration, a shaggy crumble you squeeze together rather than stir. It ferments slower and drier, and pushes the other way: strength, chew, and a deeper, almost winey perfume.
Side by side, the 30% bowl from the batch worked below:
| The bowl | Poolish | Biga |
|---|---|---|
| Hydration | 100% | 45% |
| Flour | 226 g | 226 g |
| Water | 226 g | 102 g |
| Feels like | Pancake batter | Shaggy crumble |
Which one, when
Poolish shines where you want stretch and airiness: New York rounds that open wide without a fight, high-hydration Roman teglia, focaccia. Biga shines where the dough needs spine: drier doughs, long fermentations, and the chewy-crumbed Italian tradition it comes from.
But hold the rule loosely — both work everywhere, and the differences are seasoning rather than law. If you’re new to preferments, start with poolish: it’s harder to get wrong and easier to read.
How the calculator splits the recipe
In Pro mode, choose poolish or biga and a share of the flour — anywhere from 10 to 60%, with 30% as a sweet default. The preferment bowl takes that flour, its water (equal weight for poolish, 45% for biga), and about 40% of the plan’s yeast — never less than 0.05 g, a real crumb. Salt waits for tomorrow: it would only slow the party.
Here is a 4 × 320 g New York batch with a 30% poolish, split into its two bowls:
| Ingredient | Tonight | Tomorrow |
|---|---|---|
| Flour | 226 g | 528 g |
| Water | 226 g | 249 g |
| Yeast (IDY) | 0.7 g | 1 g |
| Salt | — | 19 g |
| Oil | — | 19 g |
| Sugar | — | 11 g |
Look closely and it’s the same recipe — the totals of flour, water and yeast match the no-preferment batch to the gram. A preferment changes the order of things, never the amounts.
The night before
With a preferment on, the schedule grows a new first step: mix the preferment 8–12 hours before the dough. The calculator takes 40% of your plan’s total hours and holds it inside that window — for the 8-hour example above, the poolish mixes 8 hours ahead.
The method is unceremonious. Whisk the water and yeast, add the flour, then stir a poolish until no dry spots remain — or squeeze a biga into rough lumps and stop while it still looks wrong. Cover, leave on the counter, buonanotte.
Ripe poolish is domed, carpeted with bubbles, and just starting to sag in the middle; ripe biga has puffed and pulls into airy strands when torn. Both smell sweetly fermented — boozy means they’re past their best, not ruined.
And the fridge still stacks on top: night-before poolish, dough-day mix, then a cold nap before baking. The cold fermentation guide covers that half of the plan.
Questions from the counter
Which split should I pick?
30% is the classic compromise and the calculator’s default. Drop toward 10–20% for a subtle background note; push toward 50–60% for maximum character — knowing a big preferment leaves less margin, because most of your flour is already fermented before the dough day starts.
How ripe is ripe?
Use it when it’s clearly alive but not yet collapsing: a poolish domed and bubbling, dimpling in the center; a biga puffed and airy inside. The window is forgiving — hours, not minutes — and a slightly young preferment simply brings a little less of everything.
Why isn’t my poolish a pourable batter?
Big split, dry style. The calculator caps the preferment at 95% of the recipe’s water so the final mix always has some left for dissolving the salt — a 60% split on a 56%-hydration thin & crispy ends up a touch stiffer than the textbook batter, by design.
Can I use a poolish with sourdough?
No — and the calculator won’t offer it. A sourdough starter already is a preferment, just with wilder tenants; stacking a second one on top double-spends the same flour. Pick one head start per dough.
Does a preferment make the dough ready sooner?
No. The calculator keeps the total yeast dose and your hours exactly as planned; the preferment just relocates part of the fermentation to the night before. What you gain is flavor, stretch and color — not speed.
Tonight, one small bowl
Flip the calculator into Pro mode, choose poolish or biga, set the split — it weighs both bowls and writes the night-before step into your schedule.
The clock is a suggestion. The dough is the boss. In bocca al lupo!
Impasto is a free pizza dough calculator for Neapolitan, New York, Roman, Sicilian, Detroit, thin crust and focaccia doughs — flour, water, salt and yeast weighed in baker's percentages, with the fermentation schedule written for you.