Cooking
Dough hydration
Calculate baker’s hydration from flour and water weights.
Calculators / Cooking / Sourdough levain build
Sourdough levain build calculator
Build a levain mass and hydration while accounting for flour and water in the starter.
On this page
Flour to add90g
Water to add90g
Total flour in levain100g
Calculator controls
How to calculate
Build a levain mass and hydration while accounting for flour and water in the starter.
Flour to add =
total/(1+hydration/100)-starter/(1+starterHydration/100) gWater to add =
total-total/(1+hydration/100)-starter+starter/(1+starterHydration/100) gTotal flour in levain =
total/(1+hydration/100) gWorked example
- Desired levain mass (g): 200
- Target hydration (%): 100
- Starter mass (g): 20
- Starter hydration (%): 100
- Flour to add: 90 G
- Water to add: 90 G
- Total flour in levain: 100 G
Assumptions and limits
Hydration is water mass divided by flour mass, not a percentage of total levain mass. This is ingredient arithmetic, not fermentation or food-safety guidance.
Results are rounded for display; calculations use unrounded values. Read our calculation methodology.
Understanding the result
Build a levain mass and hydration while accounting for flour and water in the starter. Subtract the starter’s flour and water separately from the target flour and water. Both additions must be nonnegative.
When this tool is useful
Subtract the starter’s flour and water separately from the target flour and water. Both additions must be nonnegative.
Understanding your inputs
| Input | Example |
|---|---|
Desired levain mass (g) total | 200 |
Target hydration (%) hydration | 100 |
Starter mass (g) starter | 20 |
Starter hydration (%) starterHydration | 100 |
Frequently asked questions
What does this estimate leave out?
Hydration is water mass divided by flour mass, not a percentage of total levain mass. This is ingredient arithmetic, not fermentation or food-safety guidance.
How do I check the example?
Use the stated units and the formula below. Keep full precision until the final answer; change one input at a time to see its effect.