How rum is made
Tropical heat ages rum so fast that about 10 percent evaporates from the cask every year.
- stations
- 6
- things upstream
- 30
- raw sources
- 13
- steps from the ground
- 6
The short version
Rum is fermented and distilled sugarcane, usually from molasses, the dark syrup left after sugar is made. Yeast ferments the molasses diluted in water, and the mash is distilled in pot or column stills. Many rums then age in oak barrels in hot climates and are blended for a consistent flavor.
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Cut and press the cane
Cane is cut near the ground, where the sugar is richest, and milled to squeeze out its juice. Cane is 63% to 73% water and about 12% to 16% sugar.
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Ferment the sugars
Most rum is fermented from molasses, a by-product of sugar making. French-speaking islands such as Martinique often ferment fresh cane juice instead. Yeast and water are added. Slow-working yeasts build up more fruity esters.
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Distill the wash
The fermented liquid is distilled in a pot still for a heavy, flavorful spirit, or in a column still for a lighter one. Most rum comes off a column still.
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Age in the tropics
The clear spirit goes into barrels, often used bourbon casks. Heat speeds the aging, so the angels' share, the amount lost to evaporation, runs about 10% a year, against about 2% in Scotland or France.
about 10% lost per year
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Blend for consistency
Casks of different ages and stills are blended to the house taste. Light rums are filtered to remove color gained in wood, and caramel may be added to dark rums.
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Bottle at strength
Water brings the blend to drinking strength, and it is bottled. Many countries require rum to be aged for at least one year before it can be sold as aged.
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Worth repeating
- The first recorded rum production, aside from cachaça, took place in Barbados.
- The Royal Navy's rum ration was issued at 100 degrees UK proof, 57% alcohol by volume, because that was the only strength that could be tested with gunpowder.
- In Brazil, the spirit made from cane juice is called cachaça, not rum.
- Rum was so valuable in early New South Wales that convicts could be induced to work for it.
Back to the ground
Follow every input upstream and rum starts as these 13 raw sources.
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Sources
Cite this page: "How rum is made." Assembly Line, 2026-11-03. https://assemblyline.org/make/rum