Neapolitan Pizza (Naples)

Naples water is hard. Not uniformly hard (the city's supply comes from multiple sources, principally the Serino springs in the Terminio-Tuoro limestone mountains), but in the centro storico where Neapolitan pizza was born, the hardness typically runs around 38–42 French degrees, or roughly 380–420 mg/L as calcium carbonate. That is a lot of mineral. The dominant ions are calcium and bicarbonate, which is characteristic of karst limestone aquifers: the water dissolves its way through the rock and carries the rock's chemistry with it. For pizza dough, this mineral load does several things. The calcium strengthens the gluten network, producing a dough that is elastic and extensible rather than slack. The bicarbonate creates a mildly alkaline environment that affects Maillard browning: it is part of why Neapolitan pizza develops its distinctive leopard-spotted char in a 485°C wood-fired oven. Sodium at around 25 ppm is moderate and separate from the salt added to the dough (the AVPN specifies 50–55 g of salt per litre of water in the dough recipe).

There is a persistent myth that Naples water is uniquely responsible for the quality of Neapolitan pizza. Enzo Coccia, one of Naples' most respected pizzaioli, has argued convincingly that technique, flour handling, and fermentation management matter more than water chemistry. He is right that water alone does not make the pizza.

But the local water is not irrelevant either. A very soft water would produce a slacker, less structured dough. A water high in sulphate would introduce dryness and bitterness to the crust. The Naples profile, with its calcium-bicarbonate dominance and relatively low sulphate and chloride, produces a dough that behaves the way generations of pizzaioli learned to work with it. Replicating that water will not make you a Neapolitan pizzaiolo, but it removes one variable from the equation.