It was back in the 17th century when sugar was still referred to as 'White Gold' when Rum was first produced. Initially it was produced as a means of maximising profits off of the leftover molasses, gained when refining sugar. These molasses were then distilled into the spirit drink we now know as Rum. Today Rum is not just made from molasses but also pure sugar cane juice.
Did you know that it takes roughly 2.5kgs of pure molasses to produce just 1 litre of rum distillate?
Rum, though doesn't legally need to be produced anywhere in particular, does have a rich history in the Caribbean Islands as well as in countries such as Cuba. This is due to the fact that these are the regions where sugar cane is grown.
There are two fundamentally different ways that Rum can be distilled; in a Column Still or a Pot Still.
A Column Still (often known as a Single or Coffey Still) is a continuous still where the distillate is constantly being refined and re-distilled. This re-distillation process helps to purify the resulting spirit base as well as making a lighter, cleaner and more neutral base spirit. As you may have guessed this is how White (or Silver) Rums are produced, as well as Vodkas, which are lighter in style and less aromatic/textural than Dark or Aged Rums. The spirits produced from Column Stills generally speaking won't be aged in oak and will rely on the lightly fruity aromatics of the sugar cane to give it its flavour.
A Pot Still has a large drum and the sugar cane juice, or molasses, will undergo a much longer fermentation process than those that would go through a Column Still. This longer fermentation process (of sugars/molasses, water and yeasts) produces much more complex flavour compounds. This base is then distilled, collected, condensed and then redistilled once, maybe twice, to gain the final base spirit. As this has only been redistilled once or twice, instead of multiple times, the resulting base spirit is more textural, heavy and more flavourful. This makes for a spirit much more likely to bond with the oak in its long ageing process.
Ageing of Rums
White/Silver Rums will spend no time in oak. Light Rums will spend up to 6-8 months in oak. Finally, Dark/aged rums will spend at least 1 year ageing - often a lot longer.
When Rums age in the Caribbean Islands they evaporate from the barrels a lot quicker - this leaves less spirit in the barrel which results in a greater surface area ratio. The resulting spirit then has more of an oakier flavour as more spirit surface area is in contact with the oak. Though, these Rums will need to be constantly topped up to ensure a mellow ageing process.
Rums are often then brought to a cooler climate (comparitively) where they shall undergo longer ageing still in new barrels. Longer ageing in cooler temperatures allows for a more integrated oak flavour into the spirit thus making a more complex Rum.
Produced in a Column Still and are quite light in texture and aromatics. They are often the most popular worldwide due to their ease of consumption and application to cocktails. Bacardi is the largest White Rum producer in the world.
Produced in either Pot or Column Stills, sometimes even a blend of both. These will most likely be heavier or more aromatic White Rums which have been very quickly aged or had added caramel to them. The caramel added is used to darken the Rum and give it an aged characteristic to it, it rarely adds much complexity to the aromatics.
Produced in Pot Stills and have a high ester level. This will almost exclusively be aged for the mid-long term in oak barrels. These barrels will be a mix of American or French oak but most likely American (ex-Bourbon).