Preferment calculator (poolish and biga)
Give the total flour of your recipe, its hydration and how much of the flour goes into the preferment. The calculator splits the flour and water between the preferment you mix the day before and the final dough, so the finished dough keeps the hydration you planned.
Runs in your browser: nothing you enter is sent anywhere.
How to use it
- Choose poolish, biga or custom (then enter its hydration).
- Enter the total flour of the recipe, the dough hydration and the salt, all as baker’s percentages of the flour.
- Enter the share of the flour that goes into the preferment.
- Mix the preferment amounts the day before; next day add the final dough flour, water and salt.
How it works
- Preferment flour = total flour × share
- Preferment water = preferment flour × preferment hydration
- Final dough flour = total flour − preferment flour
- Final dough water = total flour × dough hydration − preferment water
- Salt = total flour × salt percentage, all in the final dough
Worked example
1000 g of flour, 70 % hydration, 2 % salt, a 30 % poolish:
- poolish: 300 g flour + 300 g water (600 g);
- total water 700 g, so the final dough gets 700 − 300 = 400 g water and 700 g flour;
- salt 20 g; the dough weighs 1,720 g.
Tips
- Weigh everything; cup measures are too rough for hydration.
- A poolish is ready when it is bubbly and just starting to collapse; a biga when it has domed and smells pleasantly sour.
- If the recipe adds milk, eggs or oil, they bring their own water or fat; keep them in mind when you set the hydration.
Frequently asked questions
What is the difference between poolish and biga?
Both are made the day before from part of the flour, water and a little yeast. A poolish is a batter with equal weights of flour and water (100 % hydration); a biga is a stiff dough, usually around 45–60 % hydration. In this calculator biga means 50 %; choose Custom for another value.
How much of the flour should go into the preferment?
A common range is 20–50 % of the total flour. More preferment gives more flavour and a faster final rise; very high shares can make the dough slack and sour. 30 % is a frequent starting point for a poolish.
Why does the final dough get less water?
The water in the preferment counts towards the dough's hydration. With 1000 g of flour at 70 % there are 700 g of water in total; a 30 % poolish already holds 300 g, so the final dough gets only 400 g.
Where does the yeast go?
The calculator leaves yeast out because the amount depends on time and temperature. A poolish for 12–16 hours at room temperature is often made with a very small pinch of instant yeast; any extra yeast is added to the final dough.
Can I use it for a sourdough levain?
Yes, as a custom preferment: enter the levain's hydration (100 % for a liquid starter) and the share of the flour it carries. The sourdough starter calculator helps if you build the levain in several feeds.