Pizza Dough Hydration Explained: The Sourced Numbers, and What Each Band Does

Hydration is water weight divided by flour weight, expressed as a percentage. That is the definition and there is nothing hidden in it. It is one line of what bakers call baker's percentage, a system in which flour is always 100 percent and every other ingredient is stated as a percentage of the flour weight rather than of the total. A dough at 60 percent hydration with 2.5 percent salt contains, for every 1,000 g of flour, 600 g of water and 25 g of salt. The percentages will happily add up to more than 100 and that is not a mistake, it is the point: the system is a set of ratios to flour, which is why it scales to any batch size without any further arithmetic.

Now the Neapolitan figure. The AVPN's International Regulations specify a dough of 1 litre of water to 1,600 to 1,800 g of flour. One litre of water weighs 1,000 g, so the arithmetic is ours to do and here it is: 1,000 divided by 1,800 is 0.556, which is 55.6 percent, and 1,000 divided by 1,600 is 0.625, which is 62.5 percent. The AVPN document prints no percentage anywhere. The band is our derivation from its ratio, and we say so plainly rather than presenting it as something the AVPN wrote.

Commission Regulation (EU) No 97/2010, the instrument that registered Pizza Napoletana as a Traditional Speciality Guaranteed, states the same kind of ratio with none of the range: 1 litre of water to 1.8 kg of flour. That is 1,000 divided by 1,800, so a single fixed 55.6 percent. The two documents are compatible rather than contradictory here, since the EU figure sits exactly at the dry end of the AVPN's band, but they are not the same instruction. One names a point, the other names a range, and if you have read a source claiming that "the AVPN specifies 62 percent hydration" or "Neapolitan is legally 55 percent", both of those are somebody's arithmetic being passed off as somebody else's rule.

These are the figures we already compiled and attributed style by style on our pizza oven temperature chart, reproduced here with the same attributions. The source column is the point of the table. A hydration number with no authority behind it is a rumour, and most of the ones circulating online are copies of copies.

Read the Roman row carefully, because it is the honest one. America's Test Kitchen publishes Roman al taglio at 82 percent. The Perfect Loaf publishes it at 69 percent. That is a 13 point gap between two respected, published sources on the same named style, and it is not a typo on either side: they are describing different doughs and different handling under the same name. They disagree, and we are not going to average them into 75.5 percent, a figure neither of them published and nobody could cite. If you are chasing Roman al taglio, pick a source and follow it end to end rather than blending two recipes that were never designed to meet.

The wider pattern in that table is worth more than any individual row. Hydration climbs steadily as you move down the list, and so does bake time. That is not a coincidence, and it is the mechanism the next section is about.

Here is the relationship that makes the whole table make sense: hydration runs inversely to how long the pizza is in the oven. Water leaves dough as steam, and steam takes time. The longer the bake, the more water escapes, so the more water the dough needs to start with in order to finish moist rather than dry and biscuity.

Put the two extremes next to each other. The AVPN and the EU regulation both specify a bake of 60 to 90 seconds, the only major figure the two documents agree on. In 60 to 90 seconds at a floor temperature that both documents put somewhere between 380 and 485°C, almost no water gets out of the crumb. The EU regulation even specifies how far the heat gets: the dough is to reach an internal temperature of 60 to 65°C during that bake, which is hot enough to set the structure and nowhere near enough to dry the interior out. A dough starting at 55.6 percent finishes soft because the water never had a chance to leave.

New York style is the other end. The commercial deck oven manuals and test kitchen figures we compiled put it at 500 to 600°F for 4 to 12 minutes, and a 12 minute bake is roughly eight times the duration of a 90 second one. Over that long a bake, water genuinely leaves. Which is exactly why New York hydration is published at 57 to 62 percent, sitting at and above the top of the Neapolitan band, and why the further you go down the table into pan styles with long bakes, the wetter the published dough gets: Detroit at 71 to 75 percent, Sicilian at 73.5 percent. Those doughs are wet because they are going to spend a long time losing water.

Translating the table into behaviour, in order.

55.6 to 62.5 percent, the Neapolitan band. This is the band both governing documents describe, and it is the most forgiving dough to handle in the entire table. It is firm enough to stretch without thinning to a hole, firm enough to sit on a peel without slumping, and dry enough that it releases cleanly. It is also the band that survives being cooked in 90 seconds, since it is not carrying water it has no time to shed. If you are new to a high heat oven, this is where to start, and it is not a compromise: it is what the style is specified as.

57 to 62.6 percent, the New York and Grandma zone. New York at 57 to 62 percent and Grandma at 62.6 percent, both per the sources in the table, sit here. The dough is noticeably softer at the bench, stretches larger with less resistance, and produces the chewier, more open crumb the style is known for. Handling cost is real but modest. This is the band most home bakers migrate to once they can reliably launch, because it rewards a longer bake in an ordinary oven or on a steel.

69 percent and up, the pan and tray styles. Roman al taglio at 69 or 82 percent depending on whose recipe you take, Detroit at 71 to 75 percent, Sicilian at 73.5 percent. At this point the dough stops behaving like something you stretch by hand and starts behaving like something you pour, press and coax into a pan. That is not a defect, it is how those styles get their airy, custardy interiors. But notice what all three have in common: they are baked in or on a pan, which means the dough is supported on all sides while it sets. High hydration and free launching onto a bare stone are an awkward combination, which is the next section.

Every point of hydration you add buys you crumb and costs you handling, and the cost lands in two specific places.

Stretching. A wetter dough is more extensible and less elastic, which sounds like an advantage right up until the moment the centre of the disc thins faster than you intended and opens into a hole. Wet dough gives way rather than pushing back, so it does not tell you when to stop. The technique that keeps it intact, working from the centre outward and letting gravity do the last of the work rather than pulling, is in how to stretch pizza dough, and the failure mode itself is diagnosed in why does my pizza dough tear. A bench scraper stops being optional above about the New York band, because slack dough will not lift cleanly off a worktop with fingers alone.

Launching. This is the bigger problem. A wet dough presses more of its surface into contact with the peel and pushes moisture through whatever you dusted with, so the window between "topped" and "stuck" gets shorter the wetter the dough is. The fix is the same one that works at any hydration, just applied with more urgency: launch from a wooden peel rather than slick solid metal, dust with semolina rather than fine flour, build fast, and shake test before you walk to the oven. The full method is in how to launch a pizza.

There is a limit to how much water you can add, and it is a property of the flour rather than of your recipe. Flour absorption is the share of its own weight in water that a flour will take up, and it is a measured, published specification, not a feel.

Commission Regulation (EU) No 97/2010 specifies flour with an absorption of 55 to 62 percent, alongside the rest of its flour spec: W 220 to 380, P/L 0.50 to 0.70, stability 4 to 12 minutes, falling number 300 to 400, dry gluten 9.5 to 11 g percent, and protein 11 to 12.5 g percent. Read the absorption figure next to the recipe and the whole thing clicks into place: the regulation calls for a dough at 55.6 percent hydration using a flour specified to absorb 55 to 62 percent of its weight in water. The recipe is not sitting where it sits by tradition or taste. It is sitting exactly where the specified flour can hold the water.

That is also the explanation for the AVPN's range rather than a point. The AVPN says 1,600 to 1,800 g of flour per litre, and its own recipe page attaches the reason: the quantity depends on the degree of absorption. A flour at the top of the absorption spec can carry the litre of water at 1,600 g and give you 62.5 percent. A flour at the bottom of it needs the full 1,800 g and lands you at 55.6 percent. Same litre of water, different flour, different published percentage.

Practically, this is why the same recipe behaves differently in two kitchens. Push past what your flour absorbs and the surplus water never enters the dough, it stays on the outside as slack and stickiness. That is what a "too wet" dough usually is: not too much water in the abstract, but too much water for that flour. Italian pizza flours state this in the strength language the EU spec uses, which is why a bag such as Caputo Pizzeria is published with a W value rather than only a protein percentage, and why an American protein number alone does not tell you what a flour will hold. That gap between the two labelling systems is the subject of pizza flour protein content, and the shopping decision is in best flour for pizza dough.

One more consequence worth naming. Because hydration is a ratio to flour weight, it is meaningless without knowing how much dough you are making in the first place. The dough ball weight that goes with these percentages, and the arithmetic behind it, is in how much dough per pizza. And because water is only one of the four ingredients, the other two ratios that decide how the dough ferments are in salt and yeast ratios and cold ferment vs same day dough.