I came across a Facebook post recently:

“I’ve been dabbling with aging my own rum. I put a couple liters of the overproof unaged Wray & Nephew into a two-liter oak cask. Anyone have an idea how long it should sit before it mimics the 17-year Wray & Nephew used in the original 1944 Mai Tai?”

After removing my palm from my forehead, I realized it was time to fire up Ye Olde Reality Generator and shed some light on this all-too-common question.

The glib answer, provided by Mrs. Wonk, is “seventeen years.” However, even that obscures fundamental truths about spirit-making that should be understood by anyone going the age-it-yourself route. Let it be known–I understand that small-cask aging at home and in bars is “a thing.” I’ve enjoyed many a barrel-aged cocktail, and I’m not dismissing the small-cask idea out of hand.

So then, let’s look at some hard truths about why you won’t come anywhere close to recreating the revered, extremely expensive ($50,000/bottle) Wray & Nephew 17 year rum at home with your two-liter cask, despite what this video says.

1) Your kitchen counter or back bar likely does not replicate the Jamaican climate. Unless you heat your home to 100 degrees F and induce wide temperature swings and extreme levels of humidity, you’re nowhere close to replicating the push, pull and evaporation of the spirit through the wood that tropical aging induces. The angel’s share evaporation plays a big part in creating flavors during aging.

Heck, your house probably doesn’t even come close to the chillier climate and temperature swings encountered during “continental aging,” which occurs in England, Scotland, or France. But if you must, keeping your cask in a (well-ventilated) workshop or barn is much more effective for enhancing the aging process. Still, even if you achieved continental levels of aging at home, seventeen years in the Caribbean roughly equates to fifty-plus years of continental aging. Put that in your calendar and let’s chat again in 2068.

2) Your mini cask is probably virgin oak. That means it’s not ex-bourbon, ex-wine, or ex- anything. Freshly made oak casks transmit a large amount of wood sugars, tannins, and vanilla flavors into the spirit the first time they’re used. These flavors are signature notes of bourbon.­ There’s a reason why bourbon, by law, must be aged in never-before-used oak casks – it imparts this signature flavor profile. It’s also the reason why other spirit makers use ex-bourbon casks –much of those initial extractive flavors have been toned down. Now, we don’t really know what type of casks Wray & Nephew 17 was laid down in, but I’m guessing it wasn’t virgin American oak.

If you’re going to age rum at home, I’d suggest neutralizing the cask somewhat by aging something like whiskey in it first. Otherwise, your spirit may well come out tasting like bourbon. In a nutshell, the more a cask is used, the more neutral it becomes.

3) While we don’t really know the exact nature of the casks the original Wray & Nephew 17 was laid down in during the 1920s, the odds of it being a three-, five-, or even ten-liter cask are slim to none. Simple geometry dictates that the size of a cask impacts of the quantity of spirit in direct contact with the wood; the smaller the cask, the higher percentage of contact. Aging is a symphony of different chemical processes, not a lone violin. Dramatically altering the spirit to wood contact ratio turns up the volume on some processes and reduces it on others. Different flavor profiles are the result.



Update – August, 2020 – We now know a bit more. See this more recent story for details.

4) Just as the amount of wood contact impacts the symphony of aging reactions, so does the proof of the spirit. Rum casked at 50 percent ABV will have a different taste than rum aged at 75 percent ABV, even if you dilute the second to match the ABV of the first afterward. The exact statistic depends on the distillery, but new Jamaican rums are put into casks at a higher ABV than the 63 percent ABV of today’s Wray & Nephew overproof in the bottle. Also, after your modern day Wray & Nephew overproof comes out of your cask, its ABV (around 63 percent) will be far higher than Wray & Nephew 17 – once source says it was bottled at 43 percent ABV.

5) It’s often a surprise to rum newcomers that distilleries don’t make the exact same rum from batch to batch. Rather, they use different recipes and fermentation times to produce different “marques,” which have wildly different flavor profiles. (See here for more information on Jamaican marques.) Any Jamaican distillery can make rums ranging from light, nearly tasteless rums to extremely pungent, high ester flavor bombs.

What marque(s) compose today’s Wray & Nephew overproof? The company certainly knows, but it remains a mystery to the rest of us. Which marques made up Wray & Nephew 17? Were they Plummer? Wedderburn? Common Clean? Light Continental? We don’t know that either, although the answers may be buried in Wray & Nephew’s archives. Suffice it to say, the odds of the current overproof having a similar ester level to classic Wray & Nephew 17 are probably not great. (However, if somebody from Wray & Nephew wants to chime in, we’re all ears.)

6) Distillation technique impacts flavor profile. It’s generally acknowledged that today’s Wray & Nephew Overproof is a blend of pot and column distillate. However, the original Wray & Nephew 17 was entirely pot distillate. How can we be sure? Because column stills didn’t arrive in Jamaica until sometime during the 1960s.

So then, with the above in mind, by all means, pour your rums in a small virgin oak barrel if you’re so inclined and enjoy the results. I’m all for whimsy and not trying to rain on anybody’s parade. Just be realistic in your expectations of what you’re creating.