In the whisky industry, creating a quality product is all about the details. Colour, nose, flavour, structure and certain other nuances of the finished product are attributable in very large part to the cask. The right wood, alongside the method of distillation itself, can elevate a liquid beyond that of its peers. Similarly, finishing spirit in the right cask can add subtle differences to a whisky, adding an additional layer of flavour and depth to an end-product, allowing for greater expression and creativity, and showcasing a distillery’s unique vision and personality. As such, the cask itself is critical tool in the distiller’s arsenal.
While the process known as cask finishing (or often double-barrelling in the USA) has in recent decades been seen as a largely whisky-centric phenomenon, it is now becoming a more widespread practice across other spirit sectors – particularly rum.
In this article, we will look at the practice of cask finishing for rum and how it adds versatility and excitement to this increasingly popular spirit. We will examine the current rum revolution and how it is following in the footsteps of gin and whisky to become a far more popular drink than it has historically been (at least over the last few decades) within the UK with a growing reputation amongst more discerning drinkers.
A close look at industry statistics will also provide a more detailed overview of the current situation, market trends, and how cask-finishing could become a powerful USP for rum producers.
We will also examine the role of cask specialists such as our own cask division, Ethimex Cask Solutions. Our expertise in sourcing and vetting over 60 different used cask types from partner distilleries and wineries around the world, primarily for delivery to our customers in the rum, tequila and whisky industries, puts us in very good stead to provide some insight for the outsider into this somewhat specialised rum-making technique.
Why Cask Finish Rum?
While whisky has been cask-finishing at a commercial scale since the 1970s, rum producers have only just started to embrace the technique over the last few years in order to introduce a greater variety of flavours and allow for further innovation within the category. A key aim is to cater to consumers’ desire for experimentation, driving trial at the expense of other spirit categories, and capturing more market share from amongst an engaged audience.
Cask-finishing has always been used to give Scotch whisky a greater spectrum of flavours. By applying the same process to rum, producers could see an increase in sales as new rum drinkers embrace exciting new expressions and premiumised products with enhanced character.
The Ideal Casks for Finishing Rum: Distilleries Leading the Way
As premium aged rum continues to grow in popularity in many key global markets, selecting the best cask types for finishing has become an essential factor in defining the spirit’s final character. Richard Bayles, Head of Division at Ethimex Cask Solutions, and also a well-known face in the global rum business, delves into the categories of casks that have proven most effective in enhancing rum, sharing his insights on some of the distilleries that are at the forefront of this trend.
Sherry casks
A good-quality first-fill Oloroso Sherry cask will impart an additional layer of richness to a mature rum, with notes of dark dried fruit (think raisins, currants, figs and dates), quite often offset with brighter citric nuances akin to orange marmalade, plus of course that classic oloroso nuttiness.
For meticulous rum-makers with time on their hands, I’d propose an original 500L criadera butt or 600L solera butt. These will yield the most impressive results since they tend to hold anywhere between 30 and 80 years’ worth of in-drink locked deep in their staves. That said, the lower internal surface area to liquid ratio still means a far longer wait than when using 250L media botas (hogsheads) and, furthermore, these original casks are increasingly hard to come by. Thankfully, supply of these rare casks is one of Ethimex’s core activities.
Cutting down fresh sherry butt staves to build 250L media botas is an alternative route if you’re seeking faster spirit evolution in the cask. However, in my experience, the sherry potency tends to diminish when applying intense heat to the staves, a necessary part of the re-coopering process.
The tendency to opt instead for ‘seasoned’ sherry butts or hogsheads (whereby brand-new oak casks are soaked with sherry for an average period of 18 months before use in the spirits sector) is so widespread that about 98% of all Sherry casks used in the spirits sector are of this type. These casks are certainly reliable for their profile consistency year on year and are especially important for larger spirits brands who know full well that there simply not enough original “solera” casks available on the market to cater for their volumes. However, these do not come close to having the punch of an original criadera butt!
From amongst our customers, a classic example of a Sherry cask-finished rum is Destilería Serrallés’s Don Q Double-Aged Sherry Cask Finish 8-year-old Rum. This well-crafted Puerto Rican rum demonstrates a very well-balanced rum with a distinct fruitcake Oloroso Sherry finish.
Full-term Sherry cask ageing:
Alongside Bourbon barrels, there is a tradition of long-term or full-term ageing in Sherry casks, as opposed to just cask-finishing. A classic example would be Ron del Barrilito from Puerto Rico. Foursquare Distillery’s Sovereignty 14-Year Blended Rum, in which certain core rum components in the blend will have spent around 11 years in oloroso Sherry casks, is another highly-regarded example.
Port casks
Some of the most remarkable secondary cask-finished rums I’ve had the pleasure of tasting have been those put through our Tawny and Ruby Port casks.
In the case of Ruby casks, the prominent fresh red fruit character that they impart on a rum (think cherries, plums and soft red fruit) creates an unusual but harmonious alliance on the palate. Tawny Port casks (available as 225L barricas or, subject to very limited availability, as 650-700L original adega pipes) lend themselves to a more integrated, richer profile with honeyed notes of apricots and dried fruit. It is claimed that high levels of residual sugar in both styles of port can result in a distinctly sweeter rum, although this is a moot point given that, even with over 100g/L of sugars in the Port wine itself, the likely introduction of sugar from the Port residues and in-drink would likely sit well below 5g per litre of cask strength rum – perceivable perhaps, but not exactly sweet.
Ron Abuelo XV Port Cask Panamanian rum is an excellent example of a rum finished in a Tawny Port barrel, giving it a rich, complex personality and depth of flavour. Again, another mention for Foursquare, whose Port Cask finished rums are widely acclaimed as some of the best of their type in the world, many of which I understand have been finished in our original ex adega 650L Ruby Port pipes.
Vermouth casks
Rum finished in Vermouth barriques is without a doubt the Marmite of the rum world! As such, Don Q’s (in)famous Vermouth-finished rum has its acolytes and its detractors, but it’s certainly worth a taste. In my view, this is one of Jaiker Soto’s true works of art. By carefully monitoring the developing impact of the Vermouth cask on a day-to-day basis (for up to six weeks), the result is perfectly executed spirit with contrasting yet not disconcerting layers of flavour – on one hand dried spice and caramel and on the other the bitter, herbaceous character you’d expect to draw out of an Italian Vermouth barrique. Insane but ingenious!
Madeira casks
Increasingly difficult to source, good Maderia casks allow this incredible fortified wine to work its magic on a rum, typically imparting a layer of walnuts, dried fruit, citrus and marmalade, dark caramel, and even a pleasantly musky edge in some instances. A hint of sweetness from the relatively high residual sugars might be detectable if the cask has held one of the sweeter styles.
And where better to seek a great example of a Madeira-cask finished rum than the island of Madeira itself where William Hinton’s Madeira Cask Finish Rum demonstrates the natural synergy of these two local products.
Marsala casks
Possibly my favourite of the ‘big four’ fortified wines – although it’s a really tough call – Marsala is also the least well known and the least used cask amongst them, as things stand, in terms of finishing rum. Despite this, it’s a gem of a cask for finishing work, yielding nutty, caramel and fried fruit flavours – along the lines of the oxidatively aged Sherries and some Madeiras, but with what I would describe as distinct tamarind-like edge.
While all our customers in the Rum sector appear to be using our Marsala casks for full-term maturation, it is worth mentioning here Worthy Park’s well-received Marsala Cask Finish as an example of a well-made Marsala-finished Jamaica Rum.
Scotch whisky casks (peated)
If you’re looking for something leftfield, but Vermouth is a stetch too far, then barrels which have held peated Scotch Whisky, most typically from the island of Islay, are a solid bet. The behaviour of phenols (the chemical compounds responsible for the smoke aromas) means that it doesn’t take much time or effort to impart peat-smoke characteristics to a rum, generating some intriguing results from early in the process.
Examples on the market are still few and far between, but Grander Rum’s superb Single Barrel Peated 12 years is an excellent illustration of how a peated cask can be used to best effect. In fact, this rum spent two whole years finishing in an Islay cask – much longer than would be typical, but allowing for much fuller integration.
Virgin Oak casks
While eye-wateringly expensive and increasingly hard to acquire, a number of our Rum-distilling customers have been experimenting with our Japanese Mizunara Oak casks for finishing (as well as full-term maturation). Results are not in yet, but we are hoping to detect the characteristic green fruit notes from early-term Mizunara ageing (the complex sandalwood and incense notes of Mizunara Oak rarely show their heads – in Whisky at least – until at least a couple of decades have gone by!).
Ethimex’s production of its unique flagship Andean Oak barrels – in use as we speak for finishing work and full-term maturation at various rum distilleries across the Caribbean and well beyond – is best showcased by the relatively recent limited-release Mount Gay Andean Oak Finish which is a blend of pot- and column-still rums aged conventionally for 13 years and then finished for up to a year in our heavy-char Andean Oak barrels. Expect herbaceous, butterscotch, soft spice, vanillin and interesting phenolic notes from this unique wood.
Tequila & Mezcal casks
No names can be mentioned yet, unfortunately, but a handful of Caribbean rum producers are busy experimenting with both our Tequila and Mezcal barrels as finishing vessels. Tequila barrels from the lowlands of Jalisco (El Valle), so long as the raw agave was sourced in that same area, tend to impart heavier herbaceous and earthy notes, whereas our barrels from the highlands (Los Altos) tend to impart fruitier, honeyed and somewhat floral Tequila characteristics. Our Mezcal casks from Durango and Oaxaca (and occasionally Michoacán) have typically held agave distillate of the prevalent smoky style. Although I have yet to taste a rum which has been finished in these, I am looking forward to a what will surely be a unique, ground-breaking flavour profile.
I should make an honourable mention here of Plantarey’s (formerly Plantation) 2023 Mezcal Cask Rum. This is a rare example of a Mezcal-finished rum, using casks from the diminutive but well-regarded Koch Distillery in Oaxaca City. It is a Trinidadian rum matured for five years in Bourbon casks, a year in Cognac casks, and its final year in Mezcal barrels. The result is impressive, and illustrates well what Mezcal, as a finish, can bring to a well-made rum.
Non-cask finished rums
While we are focusing on cask– finishing, it is worth noting that not everyone is going down this particular route at the moment. While cask– finishing has been around for a while in the whisky industry, this is a relatively new trend for rum producers, so almost any cask other than bourbon (which is the traditional cask used for ageing rum) could be considered non-traditional or innovative to one degree or another.
Some rums are not strictly “cask-finished” but are matured full-term in non-standard casks. This is part of the tradition of some producers, such as Ron del Barrilito in Puerto Rico, who use original oloroso sherry butts to mature their rum full-term, In the same vein, while not strictly matured full-term but rather half-term (still, a solid five years in sherry butts: Palo Cortado followed by Pedro Ximénez), is Williams & Humbert’s “Dos Maderas 5+5”, an exquisitely rich blended rum comprising pot-still and column marks sourced from both Barbados and Guyana
What does have a direct influence on which route a distiller takes is the availability of casks. Once-used Bourbon barrels are plentiful (because of the US requirement for all Bourbon to be aged in new barrels). Authentic, effective Cognac or Sherry barrels are much harder to source and will require the services of a dedicated cask sourcing expert like Ethimex. Almost all casks of this type will require careful vetting and repair at origin.
Why Should Distillers Cask-Finish their Rum?
Finishing casks can give a brand a distinctive identity, through range extensions or special edition expressions, that differentiates it from its competitors. Not everyone likes a heavy, dark rum as it stands, while others find even a well-made white rum lacking the character to really grab their attention and duly confine it to cocktail duty.
Distillers can create stand-out, premium-quality rums by utilising the cask- finishing technique – and, just as importantly, making it a key element of their brand story. This could appeal not just to staunch rum drinkers but to those from other sectors of the market, too.
Rum finished in Scotch or Bourbon casks can also attract drinkers who normally choose these latter spirits over rum. The technique is so well established in the whisky market that it can transfer to the rum sector and draw discerning customers who see cask- finishing as a mark of quality.
The Demand for Rum
Investing in expensive finishing barrels can be costly, especially for smaller micro-distilleries with limited production capacity. So, is the demand there to warrant this outlay?
According to the latest WSTA Report, spirit sales have declined overall. However, rum seems to be a little more resistant to a fickle buying public than other spirits – including the previous golden child of the top shelf: gin.
CGA data has shown that as of September 2023, dark rum is driving value growth, with golden still in a strong position and white rum bringing up the rear. In the 12 months to December 2023, on-trade rum sales hit £1.1 billion. Significantly, this shows rum overtaking whisky sales for the second year in a row. According to a recent report, the UK currently ranks as the third-largest market globally for rum, with a value of £1.7 billion.
In the UK, rum has a 14% share of the market, and the big winner is spiced rum, which tends to be either golden or dark, depending on the producer. The only categories currently beating rum are cream liqueurs and brandy.
It is also interesting to note that according to the CGA data, premium rums are now starting to perform better than standard rum despite a 2% drop in sales in the past 12 months. In comparison, standard rum is down 10%.
In the future, market analysts expect the premium sector to continue to show strong growth. In the UK, predictions are that this ‘luxury rum’ market will grow by around 8%, building on highly successful growth during 2022.
These figures may seem slightly contradictory, but it is worth mentioning that the considerable decline in spirit sales (most likely due to the cost-of-living crisis, increases in duty on spirits and the subsequent cost increase) has affected all sectors of the spirits’ market. As people finally start to have more disposable income to spend on premium quality drinks, they are moving more towards rum (and noticeably exotic cask-finished rums in particular).
It seems that Brits have a real taste for rum, and the more exotic, the better.
Sourcing Rum Finishing Casks – the Ethimex Solution
What is the next move for rum distilleries that want to explore the concept of cask– finishing further? The key is to source good– quality, high-efficacy casks from a reliable supplier.
Finding those exotic, elusive finishing casks to bring a whole new level of excellence to your premium and super-premium rums can be extremely challenging for a whole host of reasons and is fraught with risk. This is where Ethimex Cask Solutions comes in.
Over the past decade, Ethimex has built up a truly global cask sourcing and distribution operation, on the back of our well-known international bulk spirits business which has afforded us unrivalled access to our distillery and bodega partners’ very best used casks from a very wide range of wines and distillates. This unique arrangement means we have the advantage of being able to deliver freshly-disgorged casks, via a quick pit-stop at our regional vetting hubs, direct to our distillery and brewery customers. This assures that the casks we deliver have never been sitting dry and deteriorating in some warehouse or other.
As for virgin oak finishing casks, our Cask Division has innovated and developed new and exciting concepts over the years such as hybrid mixed-oak barrels, non-oak casks, and Ethimex’s ground-breaking Andean Oak barrels (used by a wide number of household-name rum and whisky brands), enabling distillers to push the boundaries of new rum flavour profiles and appeal to a new audiences, including the younger generation of potential rum-lovers, that may not previously have considered rum as their drink of choice.
The Future of Rum: Cask Finishing as a Business Strategy
The option for distillers to start small and build up a collection of exceptional, authentic finishing casks or niche full-term maturation casks provides a wealth of opportunities for developing and marketing a brand identity.
New rums are driving the industry forward, and distillers who embrace the concept of adding premium-quality cask-finished rums have an international audience looking for the ‘next big thing’ in spirits. Cask-finishing makes good sense, not just to enhance a brand but to drive a business forward and engage with a whole new customer base.
If you’re a commercial rum-distiller or blender want to know more about cask-finishing concepts, in particular our range of quality new and used barrels, contact us today. Use our online form and choose ‘Ethimex Casks’ under our drop-down product service section so we can personalise our response to your exact requirements.
