Arinto

Arinto is Portugal's acid specialist. In a country whose vineyards run mostly hot and dry, it is the variety growers reach for when a blend needs backbone, and it is planted from the Atlantic coast to the baking plains of the Alentejo for exactly that reason.

Its defining property is that it retains high natural acidity even when fully ripe in serious heat — an unusual and commercially valuable trait, and one that has only become more important as Portuguese summers have grown hotter. It also ages unusually well for a white grape, developing a honeyed, waxy, nutty depth after five or ten years while keeping its freshness.

The reference region is Bucelas, a small appellation just north of Lisbon where Arinto must make up at least three-quarters of the blend. Those wines are lean and citrus-driven when young, with lemon, green apple and a distinctly limey, mineral cut, and they are among the longest-lived dry whites in Portugal.

In Vinho Verde it goes by Pedernã, where it adds structure to Loureiro and Alvarinho. In the Alentejo and the Tejo it is blended with rounder, softer varieties such as Antão Vaz and Roupeiro, providing the lift they lack.

It is rarely the headline name on a label outside Bucelas, and it suffers the usual fate of a blending grape valued for what it corrects rather than what it contributes on its own. Single-varietal bottlings have become more common and make a good case for it.