Poolish vs biga

A direct dough mixes all the flour, water, salt, and yeast at once. A preferment ferments part of the flour and water first, then joins the rest at the final mix. The two preferments this calculator knows are a poolish and a biga. They differ in how much water is mixed with the flour that ferments early. They do not differ in the rule for salt or for the total hydration of the finished dough.

Total hydration is still all the water divided by all the flour. Moving water into a preferment does not change that ratio. It changes when you combine the ingredients, and how stiff the first mixture is. If the finished dough is 78% water, it is 78% whether 30% of the flour was fermented overnight in a poolish or the whole dough was mixed at once. The grams you pour at each step are what change.

Ratios

On this site a poolish starts as equal flour and water by weight, which is 100% hydration, plus the formula’s yeast, and no salt. The Roman preset puts 30% of the total flour into that poolish. You can edit the share after you pick the method. A biga, when you switch to it from the preferment menu, starts at 40% of the total flour and 50% hydration. The calculator’s own hint describes a biga as usually 45–60% hydration. That hint is this site’s editing note, not a cited study, and 50% sits inside the range the hint names.

A poolish at 100% hydration is a batter. A biga at 50% hydration is a stiff dough. The water you did not put in the biga is still part of the dough’s hydration, so it shows up in the final mix. That is why a biga can ferment a large share of the flour without becoming soupy, and why the final mix then looks wetter than the finished hydration. The water was waiting.

A poolish, worked

Four balls at 250 g on the Roman preset is 1000 g of dough at 78% water, 2.5% salt, 3% oil, and 0.15% instant yeast, with 30% of the flour in a poolish at 100% hydration. All of the yeast goes into the poolish. Salt and oil stay in the final mix. The percentages are this site’s Roman starting point, including the yeast, which is not a fermentation schedule.

The poolish is 163 g flour, 163 g water, and 0.82 g instant yeast. The final mix is 381 g flour, 261 g water, 13.6 g salt, and 16.3 g oil, plus the whole poolish. Open that Roman batch if you want to change the 30% share and watch the two columns move.

A biga, worked

The same four balls at 250 g, on the Neapolitan percentages (59% water, 2.9% salt, no oil, no sugar, 0.08% instant yeast), with 40% of the flour in a biga at 50% hydration, keeps the finished dough at 59% water. The biga is dry on purpose. The final mix has to supply the rest of the water, which is most of it, because a 50% preferment holds little water relative to the flour inside it.

The biga is 247 g flour, 123 g water, and 0.49 g instant yeast. The final mix still adds 241 g water and 370 g flour, plus 17.9 g salt. Open that biga batch to edit the 40% or the 50%. If the preferment asks for more water than the dough contains, the calculator stops instead of showing a negative amount to add.

Side by side

Both examples are four balls at 250 g. They are not the same dough. The Roman row is a wet dough with oil. The biga row is the drier Neapolitan percentages. The table is only there so the preferment columns can be compared as weights, not as a claim that one style should use one preferment.

Timing, and when to use each

This site does not publish a clock time for when a poolish or a biga is ready. Readiness depends on the yeast dose and the dough temperature, and those are your inputs, not a fixed hour. Use the yeast calculator for a commercial-yeast dose from the hours and temperatures you actually have. Use the bake planner to place those hours on a clock working backward from dinner. The planner’s durations are templates. They are not a ripening time for a preferment.

What the ratios do decide is the order of work and the feel of the first mixture. Mix the preferment first, with its flour, its water, and all of the yeast. Leave salt, oil, and sugar for the final mix. Salt slows yeast, which is why this calculator keeps it out of a long preferment. Choose a poolish when you want that early mixture to be equal flour and water. Choose a biga when you want the early mixture stiff, so more of the dough’s water is added later. Choose direct when you would rather mix once. None of those choices changes the definition of hydration.

Yeast in a preset is a starting percentage of flour, in the type you selected. It is not a promise that the preferment will be domed at breakfast. If you change the hours, change the yeast with the calculator, then bring the percentage back to the pizza page. King Arthur’s professional factors convert that dose if you switch between fresh, active dry, and instant. The conversion does not tell you how long to ferment.

What stays true either way

Flour in the preferment is a share of total flour, not an extra flour. Water in the preferment is part of total water, not an extra hydration. Yeast is weighed once. If you also add yeast to the final mix, you have left this calculator’s rule. The totals on the page would no longer match the bowl. Write down the exception if you do it, and do not expect the percentages to describe it.