Sourdough Hydration Calculator

Hydration is the ratio of total water to total flour in your dough, expressed as a percentage. It determines dough consistency, crumb structure, and fermentation speed. Lower hydration (60–65%) yields tighter crumbs ideal for sandwiches; higher hydration (75–85%) creates the open, airy crumb prized in artisan loaves. Calculating it correctly—including your starter's contribution—is essential for consistent results.

Your starter contains both flour and water. A 100% hydration starter (fed equal parts flour and water) is half flour and half water by weight. For example, 100g of 100% hydration starter contributes 50g flour and 50g water to your dough. Ignoring this can throw off your calculations by several percentage points. This calculator automatically factors in your starter's flour and water based on its hydration percentage.

A 100% hydration starter is fed with equal weights of flour and water. This is the most common feeding ratio for home bakers because it's easy to maintain and measure. Other ratios exist: stiff starters (50–60% hydration) are favored by some professional bakers for milder flavor, while liquid starters (125–130%) ferment faster and are used in some European traditions.

We recommend starting with 65–70% hydration. Doughs in this range are easier to handle, shape, and score. They're more forgiving during bulk fermentation and produce excellent results. As you gain confidence, gradually increase hydration to explore more open crumb structures. Jumping straight to 80%+ hydration can be frustrating for newcomers.

Hydration directly impacts your bread's crumb. Lower hydration (55–65%) produces a tight, even crumb perfect for toasting and sandwiches. Medium hydration (65–75%) yields a balanced crumb with moderate holes. High hydration (75–85%) creates the sought-after open, irregular crumb with large alveoli. Very high hydration (90%+) results in a glassy, translucent crumb like traditional Spanish pan de cristal.

Yes—bakers often do this via bassinage (adding water in stages). Reserve 5–10% of your recipe water, then incorporate it gradually after the initial mix. This technique strengthens gluten before full hydration, making high-hydration doughs more manageable. You can also add small amounts of flour if the dough feels too wet, but do so sparingly to avoid throwing off your salt ratio.

High hydration doughs are inherently sticky. Use wet hands when handling, a bench scraper for folding, and minimize direct contact during shaping. Proper gluten development through stretch-and-fold techniques during bulk fermentation will improve dough strength. Also, different flours absorb water differently—whole wheat and bread flours absorb more than all-purpose, so you may need to adjust.

Hydration is part of the baker's percentage system. In baker's percentage, total flour is always 100%, and every other ingredient is expressed relative to that flour weight. Hydration is simply the water percentage. For example, a recipe with 1000g flour and 720g water has 72% hydration. Salt is typically 2%, and starter ranges from 10–30%. This system makes recipes easy to scale.