The Sherry casks that Ron del Barrilito uses are so old that they impart minimal Sherry and wood flavor. Instead, they provide a perfect medium for oxidation and evaporation, the two things that make an aged product deeper, more complex and smoother. The heat of the Caribbean ages rum two to three times faster than whisky ages in the chilly climes of Scotland. The prevailing opinion used to be that single malts plateaued or declined after aging 15 to 20 years. And the deep, rich, almost profound 1942 rum I sampled from the Fernandez family barrel leads me to believe that similar limits for rum may be just as questionable.
Most countries require any rum to be aged for a year before bottling.
With some exceptions, like the Ron del Barrilito Two-Star, most premium rums are blends of several ages. The age listed on the label of a blended rum must be the age of the youngest rum in the blend. The Spanish style, epito mized by Puerto Rican rums, is lighter and smoother. The English or French is richer and more full-bodied. Among the premium aged rums I've tasted in recent months, my clear favorite is the Ron del Barrilito Three-Star.