Aging in ex-Bourbon barrels accounts for 90% of ageing. Whether in the French, English or Latin traditions, the vanilla sweetness of the Bourbon cask is essential.
Ex-cognac barrels and new barrels are also used. But a practice coming from the world of whisky, has settled among independent producers and bottlers of rum for a few years: the finish. After a long aging in a cask, the rum is left to age for a few additional months in another cask, generally an ex-wine or spirits cask, in order to give the rum an additional aromatic layor. This finish must be short so that the barrel does not soak up the rum excessively. The most common finishes are Cognac, Sauternes, Sherry and Port.