Palomino grapes grown near Jerez, Spain, are aged in a series of oak barrels called criaderas. Each criadera contains vinegar with similar flavor characteristics but have been aged for different lengths of time. When the solera–the barrel with the oldest vinegar–is tapped for bottling, it is never fully drained. A half-teaspoon sip of this vinegar will teach you that it is distinctive, with a smoky, deep, rich flavor, and that it will improve any recipe that calls for sherry vinegar’s unique presence. This vinegar comes from a 40-year-old mother; it has a 7% acidity, which is typical of Sherry wine vinegar.