I have had some difficulty finding good academic sources on the actual liquor consumed in the 18th century, so this answer is based upon the writings of David Wondrich, who is a drinks writer and mixologist who has researched the history of liquor as part of his larger study of the history of mixology. With that being said, here is what we know: 18th century liquor of all types was generally not refined 'sipping' liquor. For one thing, they were aged for shorter periods of time, typically. Rum that was made in one port would age in the barrel on sea voyages to wherever it was headed,. It might go on multiple voyages, be sold multiple times or set aside for a while in a warehouse somewhere, and thus age several years. But most rum wasn't being set aside and mellowed for 15 years like a fine Demerara today, it was being drunk at a few years old. 18th century rum was also cask strength - it would be diluted when it was consumed, if diluted at all. So it would be closer to a modern 'Navy Strength' rum at 120 proof or more, rather than the mellower 80 proof rums that are sold in most liquor stores. Finally, rum was often very pungent, having a kind of sulfurous taste and smell that was called 'hogo' - a term taken from the gaminess of wild meat, which gives you an idea of how rough the flavor can be. You can still taste and smell this in some Jamaican rums like Wray and Nephew or Smith and Cross (which purports to be an 18th century style rum). All this adds up to a rum that is not a refined sipping beverage for connoiseurs, but instead a very potent, very strong tasting liquor that is good for getting very drunk very fast. Consequently you don't see much evidence for 'sipping' rum in the 18th century - instead it was either served in mixed drinks, or served in drams (shots). Dram-drinking, like 'doing shots' today, had one purpose, which was to get drunk quickly, or at least get a buzz quickly - often people would drink a dram and be about their day (keep in mind most of the evidence I have for dram-drinking is from the later 18th century north American colonies, I do not know how prevalent it was in the early 18th century West Indies). In the early 18th century, a mixed drink was usually punch, a combination of spirits, water, sugar and citrus juice served communally in a punch bowl (the sailor's grog is a very close relative of punch, obviously). Punch drinking was a communal and rather expensive experience - a full bowl cost several shillings, which is quite a bit of money in the 18th century. Later in the 18th century we see more drinks like 'toddies' and 'slings' - essentially water, sugar, spirits (sometimes spices) without the citrus; we also see punches made by the glass at Ashley's punch house in London. Once Americans added bitters to slings in the early 19th century we see the invention of the cocktail. To return to rum, however, it was not a high-prestige drink of connoiseurs at the time. That was reserved for various forms of wine, mostly - in the English speaking world typically Madeira, Sherry, Port and Claret (AKA Bordeaux wine). It is in the 19th and 20th centuries that we see a more refined 'sipping' culture emerge around previously 'rough' drinks like rum and whisky, with longer ages and lower proofs at bottling.