As with all other aspects of rum production, there is no standard method used for distillation. While some producers work in batches using pot stills, most rum production is done using column still distillation. Pot still output contains more congeners than the output from column stills and thus produces a fuller-tasting rum.
AGEING & BLENDING: Many countries require that rum be aged for at least one year. This aging is commonly performed in used bourbon casks, but may also be performed in stainless steel tanks or other types of wooden casks. The aging process determines the coloring of the Rum. Rum that is aged in oak casks becomes dark, whereas Rum that is aged in stainless steel tanks remains virtually colorless. Due to the tropical climate common to most rum-producing areas, rum matures at a much faster rate than is typical for Scotch or Cognac. An indication of this faster rate is the angels’ share, or amount of product lost to evaporation. While products aged in France or Scotland see about 2% loss each year, rum producers may see as much as 10%. After aging, rum is normally blended to ensure a consistent flavor. Blending is the final step in the Rum making process. As part of this blending process, light rums may be filtered to remove any color gained during aging. For darker rums, caramel may be added to the rum to adjust the color of the final product.