Cask Away: The Voyages of Ship-Aged Whiskies

March 26, 2024 –––––– Danny Brandon, , , ,

Though rum is often seen as a spirit of the high seas, whisky can sometimes make that claim as well. In one way or another, ships have long played an active role in the whisky world. European distillers, of course, needed sailing ships to transport their wares to faraway markets that couldn’t be reached by horse and wagon. By the 1800s, American rye and bourbon barrels were often loaded aboard riverboats and steamships to be shipped to buyers across the country along various rivers and water routes. As Prohibition descended upon America in the 1920s, smugglers stayed one step ahead of the law by turning to the water, using watercraft to haul Canadian whisky across the Great Lakes and also to the West Coast and southern ports like New Orleans.

In the modern world, some distillers believe a whisky that spends time on a ship can age differently—and taste better. They’ve turned to ships not out of necessity but as a stylistic alternative to warehouse maturation.

Jefferson's founder Trey Zoeller and barrels of ocean-aged bourbon.

A Shore Thing

An early adopter of the practice was Jefferson’s Bourbon. According to founder Trey Zoeller, the idea came about, naturally enough, while he was spending time on a boat. “I was on a friend’s ship in Costa Rica where we would sit back on the bow and drink bourbon every evening,” said Zoeller. “I saw the bourbon rocking back and forth in the bottle and thought that, if this happened in a bottle, it would happen in a barrel.” Thus inspired, he conducted an experiment: five barrels of new-make distillate were loaded onto a ship in 2008 , and were set to spend three and a half years at sea prior to bottling. The experiment worked, and Jefferson’s still regularly releases batches (called “voyages”) of Ocean Aged bourbon today, though now it uses mature bourbon instead of new make.

Each batch starts its odyssey in the port of Savannah, Georgia, and follows a slightly different sea route that can encompass 30 ports on 5 continents, traveling between the Tasman Sea and the North Sea. The most recent batch, a wheated bourbon called Voyage 29, first crossed the Panama Canal heading westward, breaking up the trip with stops in both Tahiti and New Zealand. It then visited four ports in Australia, rounding the continent and heading north—braving rough seas and strong winds on the way to Singapore, South Korea, China, and Japan. After leaving the port of Yokohama, it started the long haul back east, making stops in both Tacoma and Long Beach before coming home to Savannah.

Jefferson’s also includes a brief sea voyage as part of the aging regimen for its new Tropics Aged in Humidity series, which aims to explore the effects of heat and humidity on whiskey. The first expression, Finished in Singapore, represented 720 barrels of matured bourbon which were sent to Singapore via an ocean carrier in July 2019. There, the whiskey was exposed to the unrelenting heat in non-climate-controlled facilities for 18 months, before making the trek back to Kentucky via another ship. The brand hasn’t disclosed how long the whiskey stayed on those ships.

Master blender Jeffrey Karlovitch is a trailblazer in the world of ship maturation, having first brushed with the style two decades ago at Kelt Cognac.

Japanese blending house Kaiyō also takes to the sea. After an initial maturation, master blender Jeffrey Karlovitch packs his whisky barrels into shipping containers and loads them onto a cargo ship that departs from Osaka and heads eastward. The whole journey takes three months, with the whiskies cruising by Los Angeles, before passing through the Panama Canal and heading for the east coast of the U.S. But instead of turning back to Japan, they continued moving east and eventually arrived at their final destination in Liverpool, where they rested for a time before bottling. The reason for that is due to strict regulations imposed by the Japanese government on wood-based products; the barrels would need to be rigorously inspected by customs for insects like termites or other environmental issues, and would almost certainly be rejected. Even though these barrels originated from Japan, they aren’t given an exception.

Interestingly, Karlovitch’s experience with ship-aged spirits dates back far further than his work on Kaiyō. Twenty-some years ago, he was the master blender of Kelt Cognac, which was one of the very first modern spirit producers to resurrect ship maturation. That aging regimen was already in place long before he joined the brand, and he was skeptical of it at first. “I actually thought it was a little bit of a gimmick when I first looked at it, to be quite honest with you,” says Karlovitch. “I like things more traditional.” He subjected the cognac to a trial: blending two batches, one ship-aged and one aged on land, to see which was better. When he tasted them, he was “completely floored” by the differences he found. Kelt, which Karlovitch still works on, also opts for a three-month-long voyage: starting and ending in Le Havre, France, and traversing across the Suez Canal.

But according to Karlovitch, ship maturation isn’t always smooth sailing. Part of that comes down to barrel choice. Kaiyō whiskies are matured in mizunara oak, which is notoriously prone to leaks and difficult to work with. His barrels lose an average of 1 to 2 liters of whisky over the course of the adventure; on one harrowing occasion, one of his barrels exploded inside a shipping container, sending its contents flying everywhere. The whole container needed to be offloaded in the port of Charleston, which meant that Karlovitch had to pay an additional tax on it. “To be honest, it definitely looked worse than it was,” he said with a laugh. He insists on using the troublesome casks for the flavors they impart, but he ages Kelt cognac in traditional Limousin French oak barrels.

There’s also the new UK-based start-up Never Say Die, which opts for a dual-location maturation between Kentucky and England broken apart by a six-week-long sea voyage. The voyage was inspired by the label’s namesake, a racehorse named Never Say Die which was born in Kentucky and prominently raced in England.

Sea Changes

Ship aging a whisky introduces a few new aspects that aren’t really seen in traditional warehouse maturation. The first aspect is added motion. Ship-aged whiskies are subjected to the ebb and flow of waves. As the waves rock the boat, the whisky sloshes around inside the barrel—leading to more interaction between the liquid and the barrel. While this can have different effects depending on char level, generally the liquid will take on stronger barrel notes: black tea, maple, vanilla, oak, and caramel. The interaction also helps to draw out unwanted congeners from the liquid, smoothing out rough edges and lessening unwanted sulfur notes. While many distillers introduce motion by routinely rolling their barrels, the motion brought by the waves is constant. Stormy waters increase the force of these waves, potentially leading to even more interaction and turning a risk into a boon.

Karlovitch says temperature variation is the key aspect of ship aging. “You can’t have hot without cold, to me, in whisky maturation,” he says. He notes that barrels will expand or contract depending on what temperature they’re exposed to, and that has an impact on the whisky inside—heat tends to bring out more flavors from the barrel, while the colder climates help to balance out the whisky. Ships are mobile, which allows the barrels to be subjected to both climates, but the exact exposure will vary based on which route is taken. Kaiyō’s route was specifically designed with balance in mind, moving the whisky from cold to hot, then back to cold. The resting period in Liverpool also serves as an additional point of coldness, bookending the whisky’s journey.

Ship maturation is not without pitfalls. Some time ago, a Kaiyo barrel exploded inside its shipping container during a voyage.

Tasting the Tides

There are few things in the whisky world that are as hotly debated as terroir. Any discussion of an unorthodox maturation process, such as ship maturation, is sure to add fuel to that fire. For these whiskies, the focus is entirely on the potential impact that sea air can have on liquid as it ages. The idea is that as these whiskies age, they will start to take on salty, briny, or minerally notes.

But are those characteristics so different from the landlubber whiskies? While not a ship-aged whisky per se, Glenglassaugh Sandend, our Whisky of the Year, was matured in coastal warehouses exposed to air from the North Sea. When tasting it blind, our panel found both notes of minerality on the nose and accents of sea salt on the finish. That’s also the case with some other single malts like Bruichladdich and Talisker, which both display maritime salinity.

And just how much impact does ship maturation actually have on taste? Kaiyō sent the Whisky Advocate tasting panel two whiskies: one that spent 3 months and 1 week at sea, and one that stayed on land the whole time. Tasting them side by side, our panelists found that the ship-matured whisky had far more complexity, with a more mellowed sweetness and hints of smoke and salt that weren’t present in the other whisky.

According to our panel, there is more aging, and decided influence, from the voyage. It’s almost two different whiskies, though not quite. If it were ice cream, one would be the standard flavor and post-voyage would be the same flavor with pleasant additions to create its own individuality, like vanilla versus vanilla butterscotch, or some other variation.

Here are some reviews of the whiskies that have aged on the high seas. We recommend tasting a few blind in a flight in a session with whiskies matured on dry land and drawing your own conclusions. It’s twice as much fun with a crew of fellow tasters. Bon voyage!

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