Sourdough Starter Feeding Calculator
To feed a sourdough starter, scale fresh flour and water relative to seed starter weight using a feeding ratio. A standard 1:1:1 ratio uses equal weights (e.g. 50g starter + 50g flour + 50g water = 150g active starter in 4-6 hours).
Use our interactive calculator below to perform instant conversions, inspect reference tables, and view worked formulas for precision baking.
Interactive Baking Calculator Widget
Adjust inputs below for instant real-time recipe formulation.
Mathematical Formula & Step-by-Step Example
Building a 300g Levain Using a 1:2:2 Feeding Ratio
- Identify target levain mass: 300 grams.
- Calculate total ratio parts for 1:2:2 ratio: 1 (starter) + 2 (flour) + 2 (water) = 5 parts total.
- Calculate 1 part weight: 300g ÷ 5 = 60 grams.
- Weigh Seed Starter (1 part): 60g carryover starter.
- Weigh Flour (2 parts): 60g × 2 = 120g unbleached flour.
- Weigh Water (2 parts): 60g × 2 = 120g water at 78°F.
- Result: 60g starter + 120g flour + 120g water = 300g active levain peaking in 6 to 8 hours.
Sourdough Starter Feeding Calculator Reference Matrix
Sourdough Starter Feeding Ratio & Peak Timing Reference Matrix
| Feeding Ratio | Starter Mass (g) | Flour Mass (g) | Water Mass (g) | Target Total (g) | Estimated Peak (75°F) |
|---|---|---|---|---|---|
| 1:1:1 (Maintenance) | 50.0g | 50.0g | 50.0g | 150.0g | 4 to 5 Hours |
| 1:2:2 (Standard Levain) | 40.0g | 80.0g | 80.0g | 200.0g | 6 to 7 Hours |
| 1:3:3 (Extended Build) | 30.0g | 90.0g | 90.0g | 210.0g | 7 to 9 Hours |
| 1:4:4 (Overnight Build) | 25.0g | 100.0g | 100.0g | 225.0g | 9 to 11 Hours |
| 1:5:5 (High Dilution) | 20.0g | 100.0g | 100.0g | 220.0g | 10 to 14 Hours |
Common Baking Mistakes to Avoid
Feeding Sourdough Starter by Volume Cups Instead of Weight
Cups of flour and water weigh differently (125g vs 240g). Feeding 1 cup flour and 1 cup water creates a soupy 192% hydration starter.
Using Chlorinated Tap Water for Feedings
Municipal chlorine and chloramines kill wild yeast and lactic acid bacteria. Use filtered, spring, or de-chlorinated water.
Mixing Dough with Past-Peak Collapsed Starter
Using starter after it collapses starves yeast of sugars and introduces excess acid that breaks down dough gluten integrity.
Discarding Excess Starter Down the Kitchen Sink Drain
Thick flour paste sets like concrete inside plumbing pipes. Dispose of discard in the trash or compost, or use in discard recipes.
Understanding Sourdough Starter Feeding Calculator in Professional Baking
Maintaining a healthy sourdough starter requires disciplined feeding schedules anchored by precise baker's weight ratios. Regular feedings supply fresh starches and sugars to sustain symbiotic colonies of wild yeasts and lactic acid bacteria.
Feeding ratios control maturation timelines. A 1:1:1 ratio consumes available food rapidly, peaking in 4 to 5 hours at 75°F. Higher ratios, such as 1:4:4 or 1:5:5, dilute acidity and extend fermentation across 10 to 14 hours, enabling overnight starter builds.
Hydration level influences starter microbiology. Maintaining 100% hydration (equal flour and water weight) balances yeast gas production with acetic and lactic acid synthesis. Lower hydration starters favor acetic acid, while wetter starters promote mild lactic flavors.
Temperature dramatically regulates metabolic rates. Ambient temperatures around 75°F to 78°F optimize yeast activity and flavor development. Chilling starter at 38°F slows metabolic rates, allowing safe weekly maintenance storage without daily feeding requirements.
Frequently Asked Questions
What does a 1:1:1 sourdough feeding ratio mean?
A 1:1:1 feeding ratio combines equal weights of seed starter, fresh flour, and water (e.g., 50g starter, 50g flour, and 50g water).
How do I know when my sourdough starter has reached its peak?
Starter reaches peak when it doubles or triples in volume, displays a domed top surface filled with air bubbles, and floats in water.
How often should I feed sourdough starter stored in the fridge?
Feed refrigerated sourdough starter once a week using a 1:2:2 or 1:3:3 ratio to maintain yeast vitality.
What flour is best for feeding sourdough starter?
A 50/50 blend of unbleached bread flour and whole rye or whole wheat flour provides optimal nutrients for robust yeast fermentation.
Related Culinary Calculators & Tools
Calculations on this page are strictly audited against official USDA bulk density metrics, NIST physical constants, and professional baking references. Reviewed by master bakers for culinary accuracy and kitchen scale safety.