Jefferson’s has long experimented with aging barrels in unusual locations and conditions. This started in 2012 with their ongoing Ocean Aged at Sea line, most recently attaining 29 different voyages and includes cask strength bourbon, wheated bourbon, and rye variations. A New York Edition was also released, which was cut with New York water for bottling after its voyage.

‍‍For Jefferson’s Tropics Aged in Humidity, according to the company’s press release, “The journey to create this special liquid was a wild one. Nine containers with a combined capacity of 720 barrels of fully matured Kentucky straight bourbon set sail for Singapore via an ocean ship in July 2019, marking the start of the journey. Following that journey, these barrels were exposed to Singapore's severe heat and humidity for an astounding 18 months resulting in a bourbon that is intensely caramelized and steeped with flavor. The extreme heat essentially slow cooks and caramelizes the sugars in the wood. The containers made their way back to Kentucky in March 2023, where Zoeller evaluated and selected the ideal flavor profile and proof point."

‍‍While the total number of bottles included in this release has not been disclosed, an average of 250 bottles per barrel would equate to a total yield of approximately 180,000 bottles. This could be more or less depending on yield and depending on whether all barrels were used for this release. Because that is an extremely high potential yield, it is more likely that not all barrels were included in this release, and we may see future editions as a result.

‍‍The bottle features a silk-screen image of Singapore on the back. Singapore’s latitude, longitude, and relative humidity are shown on a small round sticker on the front.

There’s something unique about this bourbon that makes itself evident on the nose, and then carries through the rest of the sip. Traditional scents are present; caramel, vanilla, light pepper, and a touch of leather, but they’re wrapped up in an unusual aroma that I can only describe as simultaneously savory and fruit-filled, albeit difficult to pinpoint specifically beyond that. While those scent/flavor dimensions can be present in a single bourbon, they typically compete with or contrast with one another. Somehow they work in unison here in a subtle way I’ve never experienced. This makes for an engaging start to the sip.

Light tobacco and caramel are accented by baking spices. The same unique, savory yet fruit-filled characteristic that was present on the nose is amplified on the palate, revealing a medley of bright summer fruits. Its impact is helped by the bourbon’s creamy mouthfeel, which adds a pleasing richness to its overall delivery. It’s unusual in the sense that while it seems like a very familiar overall flavor profile, at the same time it’s underscored by its uniquely rich, savory, bright fruity trait that ultimately defines it and is what sets it apart. This combination makes for a wonderfully rich, and highly drinkable sip as a result.

A slew of spices develops, consisting of cinnamon, nutmeg, and allspice. Savory tobacco, which is more refined here than when it was introduced initially on the palate, as well as dry leather are complemented by sweet brown sugar. The savory, fruity essence that weaved its way through the entire sip dissipates here, allowing a more familiar sweet-spicy mix to take over. It’s a very nice finish overall, offering a good degree of flavor that draws you back in for more.

Jefferson’s is a leader when it comes to exploring different aging conditions around the world. Their Ocean Aged at Sea experiment drew my attention almost 9 years ago, and I interviewed Trey Zoeller for more details. While I noticed unique underlying flavor characteristics with some of the initial voyages, I have admittedly lost interest in the concept as I’ve found more recent voyages do not offer notable qualities to the same degree. However, I have found them to be consistently well-rounded and approachable whiskeys and did notice some unique qualities with their Ocean Aged at Sea Rye Voyage 26, incidentally the first rye to be aged at sea.

Tropics Aged in Humidity puts barrels on a sea voyage similar to the Ocean Aged at Sea releases, but adds 18 months of aging in Singapore. It’s an island country and city-state about the size of Rhode Island that’s located in maritime Southeast Asia, about halfway between China and Australia. This plants Singapore just one degree north of the equator, which equates to about 85 miles. Singapore has what’s referred to as a tropical rainforest climate, and is in the tropical moist forest biome. This equates to a mean relative humidity of around 84%, though it ranges from about 60% to 100% based on season, time of day, and is heavily influenced by the country’s frequent rainfall. Overall the climate characteristics are even more extreme than areas in the southeast United States known to have a lot of rainfall and high humidity, such as Florida or Louisiana, which come close but don’t fall into the same overall category as Singapore.

All of this climate detail would be trivial if not for the fact that there is something clearly different going on with this bourbon’s flavor profile. It’s immediately obvious on the first sip, but subtle and hard to describe. The bourbon is well-rounded and familiar, but it has a richness that’s brought out by a kind of savory, fruit-filled flavor that weaves its way through the sip from start to finish. It’s helped by the bourbon’s texture and proof, which make for a creamy mouthfeel and ample intensity of flavor. Because I don’t have access to a baseline sample that was not aged in Singapore to compare, I cannot be certain of the exact impact the aging condition had on the underlying bourbon. At the same time, whether driven by simply the base underlying components and well-executed blending or by the tropical, high humidity aging condition, there is just something subtly different about this bourbon that is what ultimately makes it stand out. Combined with the fact that it was shipped over to Singapore to age for 18 months, you just don’t have any bourbons quite like it to compare to.

Coming in at $100, this bourbon is priced in premium territory. It comes in a bit higher than the brand’s more standard Ocean Aged at Sea Voyages, but this changes when you compare it to certain voyages such as Cask Strength or their New York Edition which are priced higher. It’s difficult to compare the fact that Tropics Aged in Humidity was aged in Singapore to much else out there, though we do see bourbons aged in certain climates such as Texas’ dry heat really having a dramatic impact on the overall flavor profile.

There is little information provided about the base blend, where it was distilled, its total age, and so on which can be frustrating for some consumers. We also don’t know how limited it really is, and given the volume of barrels that traveled it may not be very limited at all. One could also make a case for the entire concept feeling gimmicky.

But the resulting bourbon has a quality that cannot be ignored. It tastes really good, and has something unusual going on that I haven’t seen replicated anywhere else. I’m sure the cost of shuffling bourbon barrels to Singapore to age for 18 months was also not a small invoice, so there is a fixed cost built into the mix that cannot be ignored. I wish this bourbon was priced for less because I could see myself drinking it regularly, recommending it often, and giving it as a gift, but one can only buy so many $100 bottles of bourbon. Existing Ocean Aged at Sea fans will be an easy group to convince, and when it all comes down to it, I’d recommend this as a $100 splurge for those who don’t usually spend this much on a bottle.

Jefferson’s may be onto something with this experiment. I don’t have enough data to know for sure that the bourbon’s unique aging process is the key factor that made this whiskey what it is, but knowing that different climates can impart unique flavors on aging bourbon barrels seems likely. There is a large following of Jefferson’s Ocean Aged at Sea bourbon, with some critics who will always see it as gimmicky, but even they can’t really say that this concept isn’t a unique one. Jefferson’s Tropics Aged in Humidity takes the company’s aging condition experimentation to a new level, and the results speak for themselves. Ultimately, as with any bourbon, the combination of base bourbon, aging conditions, and final blending is what makes a bourbon what it is. For Tropics Aged in Humidity, those factors resulted in a really well done bourbon that’s highly approachable, immediately enjoyable, and just has some unique but subtle X factor going on with its flavor profile that makes it noteworthy.