Understanding Dough Hydration

Hydration is the weight of water as a percentage of the weight of flour. 500 g of flour with 350 g of water is 70% hydration. It is not a percentage of the total dough, and it is not a measure of how wet the dough feels.

For the flour and water relationship in a straight dough: Dough Hydration Calculator

These three are constantly confused, and they are genuinely separate calculations.

Dough hydration is the flour-to-water relationship in a dough made with commercial yeast: water divided by flour. Dough Hydration Calculator.

Sourdough hydration counts the starter as well. A starter is itself flour and water, so a dough that looks like 65% hydration on paper can really be 70% once the starter's water and flour are added to both sides of the sum. This is why sourdough recipes that ignore the starter behave unexpectedly when you change how much you use: Sourdough Hydration Calculator.

Baker's percentage is the whole formula system. Flour is always 100%, and every other ingredient (water, salt, yeast, starter, oil, sugar) is expressed as a percentage of the flour. It scales to any batch size without new arithmetic: Baker's Percentage Calculator.

Handling. Below about 60% the dough is stiff and easy to shape. Around 65 to 70% it is soft but manageable. Above 75% it is slack and sticky, and wants folding rather than kneading.

Crumb. More water gives a more open, irregular crumb, the holes people associate with good sourdough. Less water gives a tighter, more even crumb, which is what you want in a sandwich tin loaf.

Oven behaviour. Wetter dough gives more steam in the oven, which helps the loaf rise and the crust set. It also spreads more if the dough has not been developed.

Sandwich tin loaf: 60 to 65%. Easy to shape, even crumb.

Everyday white bread: 65 to 70%. Bread Dough Calculator.

Neapolitan pizza: 58 to 65%, low enough to stretch without tearing. Pizza Dough Calculator and Dough Ball Calculator.

Open-crumb sourdough: 75 to 85%, and only worth attempting once you are comfortable handling slack dough.

Wholemeal flour absorbs noticeably more water than white, so the same percentage feels much drier. Add 5% or so when switching to wholemeal, then judge by feel.

The ratio you feed a starter at sets both its hydration and how fast it ripens. A stiffer starter ferments more slowly and keeps longer between feeds.

For feeding quantities and ratios: Sourdough Starter Feeding Calculator

Comparing hydration figures between recipes that count differently. Check whether the starter is included before deciding one recipe is wetter than another.

Chasing a high number. An 85% dough badly handled makes a worse loaf than a 68% dough handled well.

Measuring flour by volume. Percentages are meaningless without scales: Cups to Grams.

Forgetting the flour in the levain. It is part of the total flour, and it changes the salt percentage as well as the hydration.