Guide · Flour

Flour strength (W)

The number that matches your flour to your hours. Get it right and the rim takes care of itself.

By the Pizza Call · Updated July 23, 2026

Flour strength is the lever that decides whether the rim comes up tall or the pizza slumps. Push a weak flour to 24 hours and the gluten lets go and the pizza bakes out flat; use a strong flour in 4 hours and it stays rubbery and barely puffs. W does one job, and it's the one that matters: it matches the flour to the timing.

What flour strength (W) actually is

W is the baking-strength index, measured on a Chopin alveograph: you blow air into a disc of dough until it bursts, and record the work it took. The longer the bubble holds, the higher the number. A biscuit flour sits around 90; a flour built for long-rise breads clears 380, and you'll feel the difference in the first minute of kneading.

Next to W you'll often see the P/L ratio, tenacity over extensibility: whether the dough springs back (high P) or lets itself be stretched (high L). For pizza you want a P/L around 0.50-0.60, which happens to be the spec Caputo publishes across its entire pizza line. So W tells you how long the flour can work; P/L tells you how it behaves under your hands.

W, protein and gluten: how they connect

Gluten forms when the flour's proteins, gliadin and glutenin, meet water and get worked. More protein of good quality means more gluten network, which means more W. So when the bag hides the W, the protein figure is your best clue: below 10.5% is weak, 10.5 to 12.5% is the medium band, above 12.5% is strong. The bands meet, with no gaps between them.

Treat that as a proxy, not a conversion. Caputo Pizzeria and Caputo Nuvola both declare 12.5% protein and behave nothing alike in the bowl, because gluten quality and the P/L balance count as much as how much protein is there. It's the best clue on the shelf, and it's still only a clue.

Don't confuse strength with grade, either. The Italian 00, 0, 1, 2 scale is a legal milling grade about ash and refinement: under the Italian decree (DPR 187/2001) a 00 is simply a flour with no more than 0.55% ash and at least 9% protein. Caputo Classica at W 220-240 and Caputo Pizzeria at W 260-280 are both legally 00, and they are not the same flour. Two separate scales, which Italian bags keep blurred on purpose.

How to choose W by fermentation hours

This is where all the practice lives. The longer the maturation, the stronger the flour has to be, because the gluten has to survive hours of enzymes and yeast working on it without falling apart. We've worked out the recommended W hour by hour, using the same method as our tool.

One caveat before you take it as gospel: this is a rule of thumb, not a standard. No mill and no disciplinare publishes an official W-to-hours chart, and the versions circulating on forums disagree with each other by a factor of three or more. W tells you how long the gluten can hold up, not how long your dough needs.

On the shelf, that means:

• W 130-190 (weak) for fast doughs, 2 to 4 hours. That's your ordinary supermarket 00: perfect for a same-day pizza, useless for long timings.
• W 220-280 (medium) for the window most home bakers use, 6 to 12 hours. This is napoletana country, and it's where most of us should be: Caputo Classica sits at W 220-240, the blue-bag Pizzeria at W 260-280.
• W 300 and up (strong) for long maturation, 24 to 72 hours, and for high hydration. The table puts 24 hours at W 330, 48 hours at W 380 and 72 hours at W 420. Caputo Cuoco runs W 300-320, Nuvola Super W 320-340, and Dallagiovanna's La Napoletana is stronger than the name suggests at around W 310. Past W 380 no ordinary retail bag will get you there on its own: at 72 hours you're blending, typically 20-30% manitoba (in Italy the word means a very strong flour rather than the Canadian province it was named after; Caputo Manitoba Oro is W 360-380) into a W 300-320 base.

How to read the bag when W isn't printed

Professional flours print the W. Plenty of supermarket flours don't, so you have to infer it. Three moves:

1. Check the protein in the nutrition panel, on the scale above. No W on the bag? W 240-280 works out to roughly 11.5-12.5% protein, so a strong bread flour is close. North American flours also drink more water than Italian 00, so expect to add 2-3% more.
2. Read the recommended use: "for pizza and long-rise breads" beats any missing number, while "for cakes and pastry" gives away a weak flour.
3. Trust the spec sheets: Caputo, Dallagiovanna, Le 5 Stagioni and the other mills publish the W of their pizza flours, and that's where to look before you buy.

Where W goes wrong

• Strong flour for a short dough. A W 350 in 4 hours never gets to mature: it bakes out rubbery and tight, and it fights you on the bench. Strength has to be spent by time.
• Weak flour for a long rise. The opposite mistake, and the more common one: 24 hours with a cake-grade 00 and the gluten caves. If a dough goes slack and soupy overnight in the fridge, this is almost always why.
• Reading "00" as "light". It's an ash grade. It says nothing about strength, and nothing about how the pizza will sit afterwards.
• Trusting protein on its own. Two flours at the same 12.5% can behave nothing alike. Protein is the clue you use when the W is missing, not a substitute for it.
• Chasing the highest W you can find. You don't need a W 400 for Saturday's pizza. Match the W to the hours and stop there.

Frequently asked questions