Sherry vinegar is made in the Cadiz province of southwestern Spain and, like balsamic, carries a protected designation. Unlike the whole range of balsamics, though, the stuff you find in stores labeled sherry vinegar varies comparatively less in quality and has fewer low-quality imitators. The base is sherry wine, and the type of grape used to make the wine determines the dryness of the vinegar. The wine is naturally fermented and then aged for at least 6 months in barrels. A sherry vinegar labeled Reserva is aged at least 2 years, and one labeled Gran Reserva is aged more than 10. The older the vinegar, the darker the color and more complex the flavor (and, the more expensive).
Even young sherry vinegars contain a lot more complexity than your average wine vinegar. This is what I love about using it in cooking—a crisp, piercing acidity balanced by considerable nuttiness and caramel notes. It brightens and deepens the flavor of foods at the same time. In the winter I splash a little sherry vinegar into a pot of beans, marinara, and hearty soups, and in the summer it’s my go-to acid for drizzling over fresh summer produce like snap peas, sliced tomatoes, and leafy salads.