How to use the poolish and biga calculator
- Enter the total flour for the whole recipe in grams.
- Choose Poolish (equal weights of flour and water), Biga (a stiffer preferment, about half as much water as flour) or My own hydration.
- Enter the share of the flour that goes in the preferment and the dough hydration for the whole recipe. The 30 and 70 percent shown are examples. Open More options for salt and yeast.
- Read the amounts for the preferment and the final dough, and the mixing list that adds up to the totals.
Formula
Preferment flour = total flour x share
Preferment water = preferment flour x preferment hydration
Final dough water = total flour x dough hydration - preferment water
Final dough flour = total flour - preferment flour; salt and yeast = percent of total flour
Hydration is water divided by flour by weight. The tool shows an error when the preferment already holds more water than the whole recipe allows.
A poolish for 1,000 g of flour
With 30 percent of the flour in a 100 percent hydration poolish, mix 300 g flour with 300 g water and 0.3 g of yeast (0.1 percent of its flour). The final dough then needs 700 g of flour and 70 percent x 1,000 - 300 = 400 g of water, plus 20 g salt (2 percent) and 2 g yeast (0.2 percent). The total dough weighs 1,722.3 g.
A biga for 800 g of flour at 40 percent and 65 dough hydration uses 320 g flour and 160 g water (50 percent), then 480 g flour and 360 g water in the final dough. Asking for an 80 percent preferment at 70 dough hydration fails, because 800 g of poolish water is more than the 700 g allowed for the whole dough.
Poolish and biga are both preferments
A preferment is a small batch of flour, water and a little yeast that you mix hours before the final dough and let ferment. A poolish is wet, with as much water as flour by weight, and is quite runny. A biga is stiffer and holds around half as much water as flour. Both add flavor and structure, and both change how you plan the hydration, because the water in the preferment counts toward the total.
To see every ingredient as a percent of the flour, use the Baker's Percentage Calculator. If you use a sourdough starter instead of a commercial yeast preferment, the Sourdough Hydration Calculator counts the starter's flour and water.
What the numbers do not decide
The percentages here are examples. Recipes use a wide range of preferment shares, hydration levels and yeast amounts, and the right ones depend on the flour, the temperature and the time you have. The yeast amount in a preferment is usually tiny, and a longer, cooler rise needs even less. If your recipe lists dry yeast but you have fresh, use the Yeast Conversion Calculator. Follow your recipe for the length of the ferment and the signs that it is ready.
Assumptions and limits
- Poolish is 100 percent hydration and biga is 50 percent in this tool. Use My own hydration for others.
- Salt and final dough yeast are percentages of the total flour. Preferment yeast is a percentage of the preferment flour.
- All weights are in grams, and the totals add up exactly before rounding for display.
- The calculation stays in your browser.
Frequently asked questions
What is the difference between a poolish and a biga?
A poolish has equal weights of flour and water, so it is liquid. A biga is stiffer, with roughly half as much water as flour. Both are mixed ahead and added to the final dough.
How much of the flour should go in the preferment?
Recipes vary a lot. The 30 percent shown is only an example. Use the share your recipe gives, and the tool will work out the water and the final dough.
Why does the tool say the preferment has too much water?
The preferment water counts toward the total water for the dough. If the preferment holds more than the whole recipe allows, the final dough would need negative water, so lower its share or raise the dough hydration.
Where does the salt go?
Salt is added to the final dough, not the preferment, in the usual method. This tool lists it with the final dough as a percent of the total flour.