Sourdough Hydration Calculator

Your sourdough starter contains both flour and water. To get accurate dough hydration, you need to account for the flour and water inside the starter. The calculator does this automatically when you enter starter weight and starter hydration percentage.

A 100% hydration starter (equal weights flour and water) is the most common and easiest to maintain. It's very active, easy to stir, and straightforward to calculate with. Stiff starters (50–60% hydration) are used in some Italian breads and produce a less acidic flavor.

Most sourdough recipes use 15–25% starter (as a percentage of flour weight). Less starter means a longer, slower fermentation with more complex flavor. More starter speeds up fermentation but can produce a more acidic loaf. 20% is a solid default for a same-day bake.

A healthy, active starter doubles in size within 4–8 hours of feeding, has a domed top with visible bubbles, and smells tangy-sweet. The float test (dropping a teaspoon in cold water) can confirm activity: if it floats, there is enough gas to leaven bread.

A widely used starting point is 100% flour, 70% water, 20% starter, and 2% salt. That gives 1kg of dough from roughly 500g flour. Adjust hydration up or down based on your flour and experience level.

Higher hydration (78–85%) generally produces a more open, irregular crumb with large holes, thin cell walls, and a chewy texture. Lower hydration (68–72%) gives a tighter, more uniform crumb that is easier to slice. Neither is better. It depends on what you're making.

Sourdough fermentation is slower and the dough loses more moisture during the long bulk ferment and cold proof. A slightly higher hydration compensates for that loss and keeps the crumb moist. The wild yeast also works better in a wetter environment.

Cold retarding stiffens the dough as fats solidify and starch absorbs water. You may find doughs that were slightly slack before retarding feel very manageable after an overnight fridge rest. If your dough is already firm, you may not need to reduce hydration for cold proofing.

Start at 75–80% when using 20–30% whole wheat. Whole wheat bran cuts gluten strands, so the dough will feel weaker at the same hydration as an all-white loaf. An autolyse of 30–60 minutes helps the bran hydrate fully before you assess the dough feel.

Yes. Enter rye flour weight separately. Keep in mind that rye absorbs significantly more water than wheat, so doughs with more than 30% rye often need 80–95% hydration to feel workable. Rye doughs never feel smooth like wheat. A paste-like feel is normal.