Enter Starter Details
Example Data Table
| Scenario | Starter Kept | Feed Flour | Feed Water | Expected Hydration | Best Use |
|---|---|---|---|---|---|
| Equal feed | 50 g at 100% | 50 g | 50 g | 100% | Daily liquid starter |
| Stiff build | 40 g at 100% | 80 g | 45 g | About 65% | Sweet dough or slow levain |
| Wet build | 30 g at 80% | 60 g | 80 g | About 122% | Fast fermentation |
| Large levain | 75 g at 100% | 125 g | 125 g | 100% | Same-day bread |
Formula Used
Starter flour: Starter weight ÷ (1 + hydration ÷ 100)
Starter water: Starter weight − starter flour
Kept starter: Current starter × (1 − discard percentage ÷ 100)
Final hydration: Total water ÷ total flour × 100
Required target water: Target hydration × final flour ÷ 100 − kept water
Seed percentage: Kept starter flour ÷ final flour × 100
How to Use This Calculator
- Enter the current starter weight in grams.
- Add the current hydration percentage of your starter.
- Enter how much starter you will discard.
- Add the flour and water planned for the next feeding.
- Set a target hydration if you want a stiff or wet build.
- Enter recipe flour and water if you need dough adjustments.
- Press calculate and review the result above the form.
- Use the CSV or PDF button to save the calculation.
Sourdough Starter Hydration Guide
Starter Balance
Starter hydration controls texture, fermentation speed, and recipe planning. A wet starter ferments fast. A stiff starter rises slower. Both can produce excellent bread. The key is knowing the water and flour inside the jar. This calculator turns each feed into clear baker percentages.
Why Hydration Matters
Hydration is the water weight divided by flour weight. A starter at 100 percent hydration has equal flour and water by weight. A starter at 60 percent hydration has less water. It feels firm and dough-like. A starter at 125 percent hydration feels loose. It may peak quickly and collapse faster.
When you change hydration, the old starter still matters. It already contains flour and water. Feeding without counting that flour can create wrong results. The tool separates kept starter into flour and water first. Then it adds the new flour and water. That gives the real final hydration.
Planning Feedings
Use the discard field before entering a feed. This shows how much starter remains in the jar. Add your flour and water weights. The calculator returns final starter weight, final hydration, seed percentage, and feed ratio. These numbers help you repeat a successful refreshment.
The target hydration fields are useful during conversion. For example, you can move a liquid starter toward a stiff levain. You can also build an exact amount for a recipe. If the target is smaller than the kept starter, discard more first.
Using Starter In Dough
Starter adds flour and water to a dough. A 100 gram starter is not just flavor. It changes dough hydration. The recipe adjustment section estimates how much flour and water come from the starter amount you plan to use. Then it shows the remaining flour and water to add.
Practical Tips
Weigh ingredients in grams for best accuracy. Stir the starter before taking a portion. Record room temperature, flour type, and rise time. Hydration is only one factor. Whole grain flour often absorbs more water. Warm rooms speed activity. Use these results as a control point, then adjust based on aroma, rise, and baking performance. Small notes make future feeding choices easier and reliable for busy baking weeks.
FAQs
What is sourdough starter hydration?
It is the water weight divided by flour weight, then multiplied by 100. A 100% starter has equal flour and water by weight.
Is 100% hydration best for every starter?
No. It is common and easy to maintain, but stiff and wet starters also work well. The best choice depends on bread style.
Why does kept starter affect hydration?
Kept starter already contains flour and water. The calculator separates those parts before adding the new feeding amounts.
Can I convert a wet starter to a stiff starter?
Yes. Use the target hydration section. It shows the flour and water needed after accounting for the starter you keep.
What does seed percentage mean?
Seed percentage is the flour from kept starter compared with total final flour. It helps estimate feeding strength and fermentation speed.
Why use grams instead of cups?
Grams are more accurate. Flour volume changes with packing, humidity, and scooping style. Weight gives repeatable starter results.
Can this adjust dough hydration?
Yes. Enter the starter amount used in your recipe. The tool estimates starter flour, starter water, and remaining recipe additions.
Does hydration control starter activity alone?
No. Temperature, flour type, feeding ratio, and starter health also matter. Hydration is one important planning factor.