Why does the starter change the calculation?
A sourdough starter (levain) is itself a mixture of flour and water. A typical 100% hydration starter contains equal parts flour and water by weight. When you add starter to your dough, you're also adding those hidden flour and water contributions, which shift the effective hydration of your finished dough.
For example: 100 g of 100% hydration starter contributes 50 g flour + 50 g water. If you ignore this and just add water to your base flour, your dough will be wetter than intended. This calculator accounts for the starter's contribution precisely.
Adjusting hydration for your flour
- Whole wheat or rye flour absorbs significantly more water. Start 5–10% higher than you would with white flour. Whole wheat at 70% may feel like white flour at 75–80%.
- High-protein bread flour handles higher hydration well. 78–82% is achievable for an open-crumb loaf if you have good gluten development technique.
- Start lower, adjust up. If you're new to sourdough, 70% hydration is forgiving. Once you're comfortable with stretch-and-fold technique, try 75–78%.
Hydration Guide by Experience Level
- 60–65%: Stiff dough, easy to handle, holds shape well. Great for beginner bakers or enriched loaves (sandwich bread). Dense but reliable crumb.
- 68–72%: Intermediate. Slightly tacky, requires some technique (stretch-and-fold). Good open crumb possible with proper fermentation.
- 75–80%: Advanced. Wet, sticky dough that spreads if not handled with care. Requires bench flour, bench scraper technique, and good fermentation timing. Excellent open crumb, crispy crust.
- 85%+: Expert level. Requires experience with extremely slack doughs, lamination technique, or baking in a loaf pan to prevent spreading. Typical of high-hydration country loaves (Tartine style).
- Whole wheat or rye flour absorbs more water: add 3–5% water per 10% whole grain substitution to maintain the same dough feel.
Related tools: Pizza Dough Calculator, Recipe Scaler, Yeast Conversion Calculator, and Cooking Converter.
Starter Hydration and Feeding Ratios
- 100% hydration starter (equal weight flour and water): the most common style. Pourable batter consistency. Peaks faster, flavored more mildly.
- 50–65% stiff starter: stiffer consistency. Slower fermentation, more acetic acid (more sour), longer shelf life between feedings.
- Feeding ratio: a 1:5:5 ratio means 1 part starter : 5 parts flour : 5 parts water by weight. Higher ratios (1:10:10) mean slower fermentation; lower ratios (1:1:1) mean faster.
- The starter hydration contributes to the total dough hydration: if your recipe calls for 200 g of 100% hydration starter, that's 100 g flour + 100 g water baked into the total dough calculation.
- Adjusting starter hydration without recalculating dough water leads to unexpectedly wetter or drier dough.
Frequently Asked Questions
What is hydration in bread baking?
Hydration is the ratio of water to flour expressed as a percentage. A 70% hydration dough uses 70 g of water for every 100 g of flour. Lower hydration (60–65%) produces stiffer, easier-to-handle dough. Higher hydration (75–85%) gives more open, airy crumb but is stickier and harder to shape.
How much levain should I use?
Typically 15–25% of flour weight. Less levain (15%) gives a slower, more acidic fermentation — good for cold retarding overnight. More levain (25%+) speeds things up but can produce a more sour, dense loaf. For a beginner's same-day bake, 20% is a good starting point.
Why does my starter hydration matter?
Because your starter contributes its own flour and water to the final dough. A stiffer 80% starter contributes less water per gram than a liquid 125% starter. This calculator lets you input your actual starter hydration so the water calculation stays accurate.
Why does starter hydration affect the recipe?
Your starter contains both flour and water. When you add levain to your dough, it contributes flour and water that count toward the total recipe. At 100% hydration (equal flour and water), 200g of starter contains 100g flour + 100g water. The calculator adjusts base flour and water to compensate for what the starter contributes, so your dough hits the target hydration precisely.
What is the difference between levain and starter?
A starter (chef/mother culture) is your ongoing culture that you maintain by regular feedings. Levain is a portion of starter that has been refreshed specifically for a bake — fed 4–12 hours before use to maximize yeast activity at peak. The terms are often used interchangeably, but technically the levain is the build you incorporate into the final dough.
What is baker's percentage in sourdough?
Baker's percentage expresses all ingredients as a percentage of the total flour weight. Hydration = total water weight ÷ total flour weight × 100. If your recipe has 500 g flour (including flour in starter) and 375 g water (including water in starter), that's 75% hydration. Always calculate hydration based on total flour and total water, not just the main dough flour and water.
Why does my high-hydration dough spread flat?
Flat spreading has four common causes: (1) over-fermentation, the gluten breaks down when the dough is left too long; (2) weak gluten development — insufficient stretch-and-fold sessions; (3) too-warm proofing temperature — fermentation accelerates and structure weakens; (4) shaping issues — surface tension not built properly before the final proof. High-hydration dough is unforgiving of any one of these, and they often compound each other.
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By Bam's Thinkery — Updated