Time is relative, as Einstein said…
The greatest genius ever has never been in the Caribbean, and we don’t know if he has never had rum, even if much Jamaican Verschnitt passed through ‘bohemian’ Germany.
Time is surely relative when talking about ageing of spirits. Rum ageing is completely different to whisky, cognac, or any other European spirit. The variables, which affect ageing, are mainly three: type and wood of barrel in which the white spirit goes to sleep; duration of ageing; and the environment of the cellar or the warehouse. What makes rum different from whisky is the third factor. Rums age in hot and humid tropical climates. On the other hand, cold climates play into the European ageing process for whisky and cognac.
It is necessary to go deep in what ageing means, and what happens over the many years the process is taking place. The wood of the barrel is the perfect material for maturation of a spirit, because the porosity of the wood allows a micro-oxygenation between the inside of the barrel and the environment of the warehouse. The ‘dialectic’ process is a slow evaporation of alcohol (usually at 65% abv.) from the barrel to the exterior, and at same time air takes its place by passing through the staves, and goes in slowly to react with the alcohol, oxidising it and creating a complex aromatic evolutio.
It’s for this reason that the wood type is very important, as well as the duration and the external conditions. As previously mentioned, the last factor causes differences between rum and European spirits. The evaporation of the liquid is faster when temperature and humidity is higher. In fact, the hydric part (35% in volume) evaporates with heat, and alcoholic part (65%) evaporates with humidity. Depending on the microclimate it can be possible to have more or less total evaporation, and even different balances and consequently different final alcoholic degrees. Some say that the best climate is where there is an azeotropic balance in the ageing, which means where water and alcohol evaporate at same speed, with no degree changes.
It’s the so-called Angel’s share, a poetic way to sweeten the bitter sip of the evaporation. Producers are brave and patient, waiting many years to see their product in the bottle. Seeing all these losses could be rather annoying. Scottish Angels reduce at 2% per year, whereas Caribbean Angels guzzle at a rate of maybe 8%. It must be that some pirates and buccaneers mistakenly ended up in heaven, and from there have taken up rumbullion. Talking with rum producers, we know that losses vary but an average of 8% seems likely, so four times more than whisky.
Four times more of annual losses means, as stated before, four times faster ageing. Here below is a useful table to compare losses.
If a rum ages four times faster than a whisky it means that, in terms of maturation, it loses pungent hints of young spirit and evolves to a fine ‘wise’ spirit, and should be considered as four times older. A 3 year old rum should be considered to be perhaps as mature and fine as a 12 year old whisky, and an 8 year rum as a 30 year whisky or more. It’s important to say that this math doesn´t apply infinitely, because after many years the process gets slower.
The conclusion is that we have to consider ‘years’ in rum different than in whisky. Time is relative, and age statements are to be read differently. Rum producers have never communicated that in a significant way, but now it’s time to focus on that. It´s needed to understand aromas, heritage, producers’ bravery and even prices of old rums.
Dan Biondi, Rum Club Italiano