96, 90, 75 percent
Distillation strength in rum: why 70 or 95 percent determines the flavor
The distillation strength is the alcohol content at which the distillate leaves the still, and it determines how much aroma remains in the rum. EU rum must be distilled below 96 percent, "traditionnel" below 90 percent, and Martinique's Rhum agricole between 65 and 75 percent.
What is distillation strength, and why does it matter?
The bottle usually shows 40 or 43 percent. That's the bottling strength, reduced with water. The distillation strength is far higher and never appears on any label. It shows how thoroughly the distiller purified the rum. The closer the distillate gets to pure alcohol, the less room remains for everything else.
That "everything else" means the congeners: esters, aldehydes, acids and higher alcohols. Their quantity is measured in g/hl p.a., grams per hectoliter of pure alcohol. A distillate at 70 percent still retains a large share of them, while one at 95 percent has only a little left. That's why an unaged agricole tastes of sugarcane, grass and pepper, while a column-still rum at 95 percent tastes almost neutral. Water only dilutes afterward; it never brings anything back.
Below 96 percent: the EU limit for rum
EU Spirit Drinks Regulation 2019/787 requires rum to be distilled to less than 96 percent, so that the distillate perceptibly retains the organoleptic characteristics of rum. At 96 percent and above, the law refers to ethyl alcohol of agricultural origin, the basis of vodka and many liqueurs. The limit thus separates rum from neutral alcohol made from sugarcane, even though both can come from the very same molasses.
A rum distilled at 95 percent is technically compliant, but only just under the line. Cuba's rules of origin make deliberate use of this margin. They blend an aguardiente at 74 to 76 percent with an activated-carbon-filtered distillate under 96 percent. The strong, clean distillate contributes lightness, the weaker one contributes aroma. Other houses, too, combine an aromatic distillate with a very pure one in this way.
Below 90 percent: what "traditionnel" and "agricole" require
The EU designation "traditionnel" or "tradicional" is stricter. It may only be used with a registered geographical indication and requires distillation below 90 percent, at least 225 grams of volatile compounds per hectoliter of pure alcohol, and no sweetening. The raw materials must come from the place of production. This combination protects rums whose character comes from raw material and distillation, not from later additions.
The designation "agricole" builds on this. It requires the same conditions, plus pure sugarcane juice, and is reserved for the French overseas departments and Madeira. Martinique goes further still. There, the daily distillate from the Creole column must fall between 65 and 75 percent. This is no accident: at this strength, the green, fresh cane-juice character that lovers of agricole prize is preserved.
Light, medium, heavy: distillation strength and body
Guyana's Demerara GI shows this relationship particularly clearly. It divides rum into three body classes based on congeners: light, under 30 grams per hectoliter of pure alcohol; medium, 30 to 300; and heavy, over 300. Light and medium rums there come from columns with two to five columns, while heavy rum comes from single or double pot stills. Still design and distillation strength thus determine the class.
For enjoyment, this means a rum distilled to a high strength isn't worse—it's simply a different tool. It forms a neutral base for cocktails or for rums that derive their flavor mainly from the cask. Low-proof distillates bring their character with them straight from the still. This has nothing to do with bottling strength. What overproof and cask strength mean is explained in the encyclopedia article on strong rum.