A bout 30 kilometres south of Naples, the town of Gragnano is surrounded by the Monti Lattari mountain range – the limestone backbone of the Sorrento peninsula. Historically, a series of natural springs fed into a larger stream called Vernotico, which flowed down the mountainside, passing through what was at the time the small village of Gragnano.

The natural slope of the terrain was fortuitous, because it allowed for the construction of a sequence of mills, which started in around 1263. During a visit to Gragnano last month, local historian Giuseppe Di Massa explained how it all worked; how gravity drove the flow of water from one mill to the next, in order to power vertical millstones – a system created for the inconsistent flow.…