Understanding Sourdough Hydration
Hydration is the weight of water in your dough divided by the weight of flour, expressed as a percentage. A dough with 500 g flour and 375 g water is at 75% hydration. It's the single number that most shapes how your dough feels and how your crumb turns out: lower hydration doughs (65–70%) are firm, easy to shape, and bake into tighter, sandwich-friendly crumbs, while higher hydration doughs (78–85%) are slack and sticky but reward you with the open, glossy holes you see on bakery Instagram.
The starter problem
Here's the detail that trips up nearly everyone: your starter is itself flour and water. A typical 100%-hydration starter is half of each by weight, so adding 100 g of it means you've added 50 g of flour and 50 g of water to the dough. If you calculate hydration from only the flour and water you pour from the bag and the tap, your real hydration is off — sometimes by several points, enough to turn an intended 75% dough into a soupy 79% one. This calculator does the accounting for you: it counts the starter's flour toward total flour, its water toward total water, and tells you exactly how much water is left to pour.
Choosing a hydration target
If you're newer to sourdough, start at 70–72%. It's forgiving to knead and shape and still produces a good crumb. Move up in 2–3 point steps as your handling improves. Flour matters too: strong bread flour and whole grains absorb more water, so a 78% whole wheat dough handles like a 73% white one. Salt, by convention, is around 2% of total flour — the calculator applies your percentage to total flour including the starter's share, which is the correct way.
Frequently asked questions
- What hydration is best for beginners?
- 70–72%. It balances an open crumb with dough you can actually shape without it sticking to everything.
- Does starter count toward hydration?
- Yes — its flour and water belong in the totals. Ignoring it is the most common reason a recipe feels wetter than expected.
- What happens above 80% hydration?
- Very open crumb and thin, crisp crust, but the dough demands strong flour, coil folds instead of kneading, and confident shaping. Work up to it gradually.