Pizza Flour Protein Content: The Published Numbers, and the Two We Could Not Get

King Arthur Baking publishes protein percentages for its own flours, which makes it one of the few American millers you can cite rather than estimate. This is its ladder, from its own article on why protein percentage in flour matters, published 25 September 2023.

Read the top two rows again, because they are the surprise. King Arthur's pastry flour is 8 percent protein and its cake flour is 10 percent, so the pastry flour is the weaker of the two. Most people assume cake flour is the softest thing on the shelf and would put it at the bottom of any ladder. On King Arthur's own published figures it is not. That is exactly the sort of thing you only learn from a miller's own numbers, and it is a good reminder that flour names are marketing categories rather than measurements.

King Arthur's framing of what the ladder means is simple: it says that the higher the protein content, the stronger the flour. Its explanation of the mechanism is that gluten strands get longer and stronger as the gluten develops, and that this produces more chewiness and more toughness in the finished product. So protein is a proxy for potential gluten, and gluten is what gives a crust its chew and its resistance. More protein is not better, it is chewier and tougher, which is a desirable thing in a New York slice and an undesirable one in a pastry.

Its style guidance, from its own article on which flour is best for pizza published 13 March 2024, follows the ladder: all-purpose for a classic crust with a crispy bottom and a little chew, bread flour for thick chewy pan pizzas with puffy crusts and a hearty chew, and its '00' Pizza Flour for Neapolitan style, which it describes as giving a crispy bubbly exterior and a puffy airy interior. Where to spend is covered in best flour for pizza dough.

Now the same question asked by a legal instrument. Commission Regulation (EU) No 97/2010 does not simply name a protein percentage for Pizza Napoletana flour, it specifies the flour as a set of measured properties.

The whole point of that table is the last row. Protein is one of seven properties the regulation cares about, and on its own it is the least informative of them. Line it up against King Arthur's ladder and the Pizza Napoletana protein band of 11 to 12.5 g percent straddles American all-purpose at 11.7 percent and stops short of bread flour at 12.7 percent. If protein were the whole story, you could bake a specification compliant Neapolitan out of a bag of supermarket all-purpose, and the reason you cannot is everything else in that table.

W is the figure that does the work Italians expect it to do. It is a measure of strength, of how much mixing and fermentation the flour will tolerate before the structure gives out, and it is why an Italian bag leads with W where an American bag leads with protein. A flour can hit 12.5 percent protein and still be too weak for a long ferment if its W is low, because the protein is present but the gluten it forms is not robust. This is the single most useful thing to understand about pizza flour labelling: an American protein number alone does not tell you what a flour will do.

Two of the other rows connect directly to decisions elsewhere on this site. Absorption of 55 to 62 percent is the physical reason the regulation's own dough sits at 55.6 percent hydration, which is worked through in pizza dough hydration explained. And stability of 4 to 12 minutes is worth reading next to the same regulation's instruction to knead for 20 minutes at low speed, a mixing time discussed in pizza dough salt and yeast ratios.

Mulino Caputo publishes specifications for its flours on its own product pages, in the Italian format, which makes it directly comparable to the EU table above.

Put the Pizzeria row next to the regulation and the fit is exact. W 260/280 sits comfortably inside the specified band of 220 to 380. P/L 0.50/0.60 sits inside 0.50 to 0.70. Protein 12.50 percent sits inside 11 to 12.5 g percent, right at the top of it. That is what a flour built to a specification looks like when you check it against the specification, and it is why the blue bag is the default recommendation for high heat Neapolitan work. If you are baking often enough that an 11 lb bag disappears in a month, the same flour comes in a 55 lb sack.

Note also that Caputo's protein figure of 12.50 percent is only marginally below King Arthur's bread flour at 12.7 percent. Two flours, almost the same protein content, used for very different pizzas and very different bakes. That comparison, more than anything else on this page, is the argument for reading the strength figure rather than the protein figure.

This section exists because refusing is the point. Both of these are real gaps in the published record, and naming them is more useful than papering over them.

Gap one: King Arthur publishes no protein percentage for its own '00' Pizza Flour. King Arthur publishes protein figures for pastry, cake, all-purpose, bread, whole wheat and high-gluten flour, and it recommends its '00' Pizza Flour by name for Neapolitan style pizza. But it does not attach a protein percentage to that product on its protein article, on its pizza flour article, or on its shop page. We looked at all three. Given how forthcoming King Arthur is with the rest of its range, the absence is conspicuous, and it means the one flour in its lineup marketed specifically for pizza is the one you cannot place on its own ladder. We are not going to estimate it from the category, because a '00' designation does not imply a protein figure.

Gap two: no W value, P/L or protein figure for Caputo Cuoco. As above, the manufacturer's own product page returned a 404 when we fetched it. Numbers for Cuoco circulate widely and are probably close to correct, but we cannot verify them at the source, so they do not appear here.

The general principle both gaps illustrate is worth stating plainly, because it applies well beyond flour: a number with no traceable publisher behind it is a rumour, no matter how many sites repeat it. That is the same standard we apply on our temperature chart, where we also decline to print an emissivity value for cordierite because we could not find one published anywhere.

Here is the misconception that costs people the most money. '00' is a grind fineness. It is not a protein grade and it is not a strength grade. The Italian numbering system describes how finely the flour has been milled and how much of the bran and germ has been removed, and '00' is the finest, most refined grade in that system. It describes the texture of the powder, not the behaviour of the dough.

Which means the sentence "I bought '00' flour, so my dough will be Neapolitan" does not follow. Two flours can both be '00' and have completely different W values, different absorption and different protein. Caputo Pizzeria is a '00' flour published at W 260/280 and 12.50 percent protein. A '00' flour milled for pastry work would carry the same designation and behave nothing like it. The grade tells you the mill's screen, and everything you actually care about is the rest of the specification.

That is why Commission Regulation (EU) No 97/2010, which is defining Neapolitan pizza in law, specifies W, P/L, absorption, stability, falling number, dry gluten and protein, and does not lean on a grind designation to carry the meaning. And it is why a bag that gives you only a '00' on the front and nothing on the back is telling you the least useful fact about itself.

What the fine grind genuinely does contribute is a smooth, silky dough surface and a fine crumb, which is part of the texture people associate with the style. That is a real property and a good reason to want it. It is just not a substitute for knowing the flour's strength.

The reason protein and strength matter at all is that they decide how much punishment the dough can take, and the punishment comes from the bake. So the flour decision is downstream of the oven decision.

For a 60 to 90 second bake, the time both the AVPN and the EU regulation specify for Neapolitan, you want a flour built for it. The regulation's own answer is W 220 to 380 and 11 to 12.5 g percent protein, and Caputo Pizzeria's published W 260/280 and 12.50 percent protein land inside that. This is the bake that needs a very hot floor, which in practice means the kind of oven ranked in best pizza oven for Neapolitan pizza, and Ooni's own guidance for the Koda 16 is to bring the stone to 715 to 850°F, which is 380 to 450°C, and to expect a Neapolitan style pizza in under 2 minutes.

For a 4 to 12 minute bake, which is what our temperature chart attributes to New York style at 500 to 600°F, with commercial deck oven manuals specifying at least 550°F for baking directly on the deck and Gozney publishing 600 to 700°F for the style, King Arthur's own recommendations apply directly: all-purpose at 11.7 percent for a classic crust with a crispy bottom and a little chew, or bread flour at 12.7 percent for a thicker, chewier, puffier result. The style comparison itself is in Neapolitan vs New York pizza.

Two knock on effects to keep in view when you swap flours. First, absorption changes with the flour, so a hydration figure that worked on one bag can leave the next one slack, which is why the EU specification pins absorption at 55 to 62 percent and why the AVPN gives a flour range of 1,600 to 1,800 g per litre rather than a single figure. Second, a weaker flour tears more readily when stretched thin, so if you have started opening holes in the centre of your discs after changing bags, the flour is a legitimate suspect alongside the handling issues in why does my pizza dough tear and the technique in how to stretch pizza dough.

One flour on this page is not for the dough at all. Semolina is a coarse durum flour used to dust the peel, where its larger grains roll under the dough instead of absorbing moisture and gripping it the way a fine '00' does. Using your expensive pizza flour as peel dust is a common and expensive mistake, and the launch method is in how to launch a pizza.