Hydration Percentage in Bread Baking

Variable %

Water — Expressed as a percentage of total flour weight; includes all liquid (milk, buttermilk, poolish water, etc.)

100%

Flour — Always the base (100%) in baker's percentage — all other ingredients are relative to flour

1.8–2.2%

Salt — Controls fermentation speed and flavour; below 1.5% bread tastes flat

0.5–1%

Yeast (instant) — Higher hydration doughs often use less yeast and rely on longer fermentation

10–30% of total flour

Preferment or starter — Poolish, biga, or sourdough starter; water within the preferment counts toward total hydration

Weigh all flour called for in the recipe. Divide total water weight by total flour weight and multiply by 100. To adjust hydration, recalculate water weight: target hydration % × flour weight ÷ 100. When working with sourdough starter (typically 100% hydration), count both the flour and water within the starter toward the formula totals. Mix, autolyse (20–60 min rest), then develop gluten through stretch-and-fold rather than kneading for wet doughs above 75%.

• Never add all the water at once to a high-hydration dough — hold back 5–10% of the water ('bassinage') and incorporate it once the dough starts to come together, allowing you to adjust for flour variation.
• Ambient humidity affects effective hydration: in a very humid kitchen, dough absorbs moisture from the air and may feel wetter than expected. Reduce water by 5 g if the dough is unexpectedly slack.
• Autolyse (mixing flour and water, resting 20–60 min before adding salt and starter) dramatically improves extensibility in high-hydration doughs, reducing the gluten development work needed.
• A wet dough is not a ruined dough — resist the urge to add flour. Use a lightly oiled or wet surface and a bench scraper instead of flouring your hands and board.
• Score high-hydration loaves deeply (at least 1.5 cm) and at a shallow angle (30–45°) to allow oven spring; if the scoring is too shallow the loaf will burst unpredictably.

• Low hydration (55–65%)

  Stiff, easy to knead by hand; bagels, pretzels, some rye breads; tight crumb, chewy

• Moderate hydration (65–72%)

  Standard lean dough; baguettes, dinner rolls, country loaves; balanced open crumb

• High hydration (75–85%)

  Tacky, requires bench skills (wet hands, bench scraper, stretch-and-fold); sourdough boules, batards; irregular open crumb, blistered crust

• Very high hydration (85–100%+)

  Pourable or near-pourable; ciabatta, focaccia, some flatbreads; baked in a pan; wildly open crumb with large irregular holes

• Whole-grain adjustment

  Whole-wheat, rye, and spelt absorb 5–10% more water than white flour; add water gradually and allow longer autolyse for bran to hydrate

• Volume to Weight Flour Conversion

  Hydration percentages are meaningless without weighing flour — the two entries are inseparable

• Pre-ferment Ratio

  The proportion of flour fermented overnight in a poolish or biga affects effective hydration and flavour

• Salt to Flour Ratio in Bread

  Baker's percentage for salt parallels the hydration calculation

1. 1.The Bread Baker's Apprentice — Peter Reinhart (Ten Speed Press, 2001)
2. 2.Tartine Bread — Chad Robertson (Chronicle Books, 2010)
3. 3.Modernist Bread — Nathan Myhrvold & Francisco Migoya (The Cooking Lab, 2017)
4. 4.Advanced Bread and Pastry — Michel Suas (Delmar Cengage Learning, 2008)

Confidence: high