After Christopher Columbus’ initial voyage across the Atlantic, He returned to the West Indies in 1493 taking with him sugar cane cuttings from the Canary Islands which were planted in Hispaniola. When travellers started to settle in the Caribbean islands, they used the easy-growing sugar cane as their economic backbone as sugar was a in such high demand.
 
Unfortunately, the production of sugar generated enormous amounts of molasses syrup for which no good use could be found to begin with. In the production of sugar, the cane is crushed to extract the juice, which crystallizes into blocks of sugar when heated. A substantial part of the liquid remains un-solidified and this waste material was called 'melazas' due to its honey-like sweetness (in Spanish, 'miel' means honey); in English, this became molasses.

It was noticed that this sticky syrup fermented when left in the sun and by the 1650s mixtures of molasses, cane juice and water were being distilled.
As the economy of sugar grew, so did the need for workers to run these plantations, which led to the ‘triangular trade’.
Ships would leave the Caribbean with a cargo full of sugar headed for North America (England and France banned the importation of alcohol from the colonies to protect their own alcohol industries). There they would trade this cargo of sugar for rum (which was distilled in America) Then they would sail to Africa where they would trade the rum for slaves and head back to the Caribbean where they would drop off the slave load in return for more molasses. The skipper would repeat this triangular trip making great profit.

The word ‘rum’ has many possible origins, although these are the most likely ones:

‘Saccharum’ – the Latin name for sugar
‘Rummage’ – The name used for a ship’s stores, where the naval spirit ration was stored
‘Rummer’ – A Roemer was a large drinking glass used by Dutch seamen who travelled to Barbados in the 17th Century.

Rum can be made from the juice of the crushed cane, cane syrup (which is the juice boiled down), or from (and usually) molasses (which is a thick black liquid by-product after the sugar juice has been boiled off and crystallized).

Whichever of the base ingredients are used, it must be fermented before it can be distilled. This means that it is mixed with water and yeast and fermented until the ‘wash’ is around 8% ABV. Fermenting has a bigger impact on rum’s flavour than it does with grain fermentation, if the fermentation is a long and slow one, the rum will be heavier due to other bacteria affecting the process.

Rums produced in pot stills, are heavier tasting, full-bodied rums, as there are still a lot of congeners left after distillation. Rums which have been through a continuous still, have the advantage of being light or heavy, depending on where they were taken out of the still.