Sourdough Starter Flour and Water Worksheet
Starter replaces some flour and water in your formula. Use this worksheet to separate what is already in the starter from what you add at mixing.
Content disclosure: Prepared with AI assistance. The examples explain arithmetic and measuring assumptions; no physical baking test is claimed.
Download the one-page worksheet (PDF)
The three numbers to record
- Total flour in the finished dough, including starter flour.
- Total water in the finished dough, including starter water.
- Starter mass and hydration: water weight divided by flour weight, multiplied by 100.
This reference assumes a starter containing only flour and water. It does not infer water from milk, eggs or other ingredients, or predict fermentation time.
If you know the starter's mass
Starter flour = starter mass / (1 + hydration / 100) Starter water = starter mass - starter flour Flour to add = formula total flour - starter flour Water to add = formula total water - starter water
A 240 g starter at 100% hydration contains 120 g flour and 120 g water. At 60% hydration, the same 240 g contains 150 g flour and 90 g water. Equal starter weights can contribute different flour and water quantities.
Worked mixing sheet: 600 g flour, 75% hydration, 2% salt
Preferment 20% of the total flour in a 100%-hydration starter. The existing baker's percentage calculator computes the rows below.
| Ingredient | Formula total | Already in starter | Add at mixing |
|---|---|---|---|
| Flour | 600 g | 120 g | 480 g |
| Water | 450 g | 120 g | 330 g |
| Salt | 12 g | 0 g | 12 g |
Add 240 g starter, 480 g flour, 330 g water and 12 g salt. The dough weighs 1062 g. Check: 480 + 330 + 240 + 12 = 1,062 g.
Your blank accounting sheet
| Formula total flour (g) | ________________ |
|---|---|
| Formula total water (g) | ________________ |
| Starter mass (g) | ________________ |
| Starter hydration (%) | ________________ |
| Starter flour (g) | ________________ |
| Starter water (g) | ________________ |
| Flour to add (g) | ________________ |
| Water to add (g) | ________________ |
| Other ingredients (g) | ________________ |
| Final mass check (g) | ________________ |
Check before mixing
- A negative flour or water addition means the starter contribution exceeds the formula total. Revise the starter amount or the formula.
- Prefermented flour percentage is starter flour divided by total flour. It is not starter mass divided by total flour.
- Do not add the starter flour and water again as separate ingredients.
Calculate your formula with starter accounting · Scale an ingredient list · All printable references