Dough hydration

Short answer

Hydration is the weight of water divided by the weight of flour, so 600 g of water in 1,000 g of flour is 60% hydration. Different styles use quite different ranges — roughly 58–65% for Neapolitan, 75–90% for Roman al taglio, and 40–55% for cracker-thin Midwest styles — and the right number depends on the flour, the bake and the texture you want.

What the number measures

Hydration is the baker's percentage for water: water weight ÷ flour weight × 100. It describes the formula, not how wet the dough feels, because flours absorb different amounts of water. A 65% dough made with a strong, high-protein or wholemeal flour can feel firmer than a 62% dough made with a weaker flour.

Some bakers count the water in other wet ingredients — milk, a liquid starter, oil — towards hydration, and some do not. Oil in particular is usually listed separately; it softens dough but does not behave like water. When comparing two formulas, check what each is counting.

Typical ranges by style

PizzaHQ's style records give these working ranges, which are approximate and overlap: Neapolitan around 58–65%; New York around 60–65%; Roman tonda, the thin crisp Roman round, around 55–62%; Detroit around 70–80%; Roman al taglio around 75–90%; Chicago tavern style around 45–55%; and St Louis around 40–50%. Other styles in the catalogue mostly fall somewhere inside that spread.

The pattern is broadly explained by how the dough is shaped and baked. Doughs that are rolled very thin and baked crisp tend to use less water. Hand-stretched rounds sit in the middle. Doughs that are pressed into a tray or pan and baked for longer can carry much more water, because the pan supports a dough that would be too slack to stretch by hand, and the longer bake has time to drive off the extra moisture.

What more water changes — and what it does not

Within a style's range, more water generally makes dough softer, stickier and more extensible, and can give a more open crumb with larger holes, provided the gluten is developed and the bake is hot enough to set it. The trade-offs are that wetter dough is harder to handle, more prone to sticking to the peel, and may need longer in the oven to avoid a gummy interior.

More water does not on its own create flavour, does not guarantee an airy rim, and does not make a dough 'better'. An open rim depends at least as much on fermentation, gentle shaping and oven heat as on hydration. A dough pushed beyond what its flour can absorb tends to spread, tear and bake flat rather than rise.

Flour absorption

Flours with more protein, and wholemeal flours with bran, usually absorb more water than weaker white flours. That is why a formula written for a strong bread flour can feel soupy when made with a lower-protein plain flour, and why recipes calling for a specific flour often give a different hydration from otherwise similar recipes.

If you change flour, it is reasonable to start a couple of percentage points lower and add water during mixing until the dough feels right, rather than trusting the number from a recipe written for a different flour. Holding back a little water and adding it later in the mix — sometimes called bassinage — is one common way of reaching higher hydrations without losing control of the dough.

Common misconceptions

“Higher hydration always makes better pizza.”

Each style has a range that suits its shaping and bake. A 75% dough baked as a thin round in a domestic oven is often harder to handle and no better to eat than a 63% dough made well.

“Two doughs at the same hydration will feel the same.”

Flour absorption varies with protein and bran content, so the same percentage can feel quite different with different flours.

“A more open crumb comes from more water alone.”

Water helps, but fermentation, gluten development, gentle shaping and oven heat matter at least as much.

What this page cannot tell you

The style ranges here are working ranges drawn from PizzaHQ's style records, not fixed rules, and individual pizzerias work outside them. This page cannot tell you exactly how a particular flour will absorb water; that varies between brands and even between harvests.

Related

Evidence

• Baker's Percentage — King Arthur Baking Company
• King Arthur Baking — flour and pizza dough technical guidance — King Arthur Baking Company
• Modernist Pizza — The Cooking Lab
• PizzaHQ editorial synthesis — PizzaHQ