Rum – Light v heavy Rum

Rum is termed 'light' or 'heavy' depending the level of flavour components or 'congeners' - products of fermentation that are not ethyl alcohol. The level of these (esters, aldyhydes and lower alcohols) is dependent on the length of the fermentation and the purity to which the rum is distilled. The fewer congeners, the lighter the rum; the more congeners, the heavier it will be.

Rum produced from a pot still or single distillation column is usually described as heavy. Multiple-column stills can produce both heavy and light rums depending on how the still is operated but column stills are usually employed to produce light rum. Light rums tend to have a short fermentation while heavy pot still rums are usually distilled from a wash formed by a long fermentation.

The odour, texture and taste of light rums are more subtle and refined than those of heavy rums, which have a heavier, more full-bodied flavour. The level of impurities in light rum is less than a third of those found in heavy rums. Distilleries producing light and heavy rums often blend the two to produce a rum having characteristics of both, usually using a majority of heavy rums in the blend.

Light rums tend to originate from countries originally colonised by the Spanish, such as Cuba, the Dominican Republic, Puerto Rico and Venezuela, while heavy rums come from countries from the former French and English colonies, including Haiti, Jamaica, Martinique, Barbados, Guyana and the Virgin Islands.