Type of Still
Another factor that affects rum styles is the type of still used. Pot stills generally produce heavier rums, richer in the congeners and esters that create flavor. Column stills produce lighter rums, stripping out more of the flavor compounds. Column stills are more efficient and therefore less expensive to operate, but it’s important to remember this isn’t an either-or proposition. Some rums are started in pot stills and redistilled in columns, and some rums are a blend of pot and column.
Type of Barrel
The kind of barrel used for aging rum affects its flavor, too. Some rums are aged in new charred-oak casks; some are aged in used whiskey barrels. Some are aged in sherry casks; some in cognac barrels. All these contribute different flavors to the finished product.
Length of Time in Barrel
This is simple: The longer a rum ages in a barrel, the more flavor compounds it will pick up from the oak.
