What does 90% hydration mean in sourdough?

90% hydration means the dough contains 90 grams of water for every 100 grams of flour, by weight. It is a baker's-percentage convention: flour is always 100%, and other ingredients are expressed as a percentage of the total flour weight.

Which sourdough styles use 90% hydration?

Pan de Cristal Light. See each style's page for the full recipe formula.

How do I convert 90% hydration into grams of water?

Multiply total flour weight by 0.9. For example, 500g flour × 0.9 = 450g water. Use the calculator below to handle salt, levain, and starter-discount math automatically.

Hydration reference · expert

Sourdough at90% hydration

Near-liquid dough territory. Extremely open, almost hollow crumb. Produces 'glass bread' effect.

Typical styles: Pan de Cristal Light

What does 90% hydration look like?

Near-liquid dough territory. Extremely open, almost hollow crumb. Produces 'glass bread' effect.

Technique for 90% dough

Dough handling requires constant wet hands, bench scrapers, and oiled surfaces. Include 5% olive oil for lubrication. Pan-baked only. Expert-level technique.

Try the calculator at 90% hydration

Adjust the target hydration, salt, and levain below. All outputs update as you type, with starter discount applied.

Total flour(g)

Target hydration(%)

Salt(%)

Levain of flour(%)

Levain hydration(%)

Flour to add: 450 g
Water to add: 400 g
Salt: 10 g
Levain @ 100%: 100 g
Total dough: 960 g
Effective hydration: 90%

How the math works

Total water = flour × hydration %. Your levain contributes 50 g flour + 50 g water — both count toward the totals. You add only the remainder as fresh flour and water.

Salt % is computed on total flour weight, not final-dough flour.

Open 90% hydration guide →

How to convert 90% to grams of water

Multiply total flour weight by 0.9. For a 500g flour dough at 90% hydration, that is 450 g of water.

Remember that the levain contributes some of the flour and water. The calculator above subtracts the levain's contribution automatically so the numbers you weigh on the counter are the real ones.