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It’s January 2026 and if you think that barrel finishes are going away anytime soon, you’re in for a rude surprise. I just heard the news that Four Roses has leaked the news that they’re developing finished bourbons for release this year. They may have been one of the last hold-outs among major Kentucky distilleries to not release a finished product of some sort.
I mention this because up until a couple months ago, I was not tracking that Castle & Key was making finished whiskies either. But I was out to eat with my friend James at Bourbons Bistro in Louisville recently and the bartender brought this bottle out for us to try – a 2025 release of Castle & Key’s Experimental Series that finished bourbon in Spanish Oloroso Sherry Casks.
Castle & Key Experimental Series
I didn’t have to do much research to write this review because this label line seems to only date back to 2024. Castle & Key has not made a big fuss about it, probably because the releases are so limited. The first Experimental Series label I found was their Restoration Rye Whiskey (63% rye, 17% corn, and 20% malted barley) finished for 18 months in Vino de Naranja (basically an Orange Liqueur) casks. For that release, only 36 barrels were used which would make it roughly twice the size of a typical Smoke Wagon Small Batch.
In late 2025, there was another rye whiskey release, this time using “Extra Old Haitian Rhum Casks.” A similar formula was followed using Restoration Rye’s rye whiskey mash bill and 18 months of time spent in the finishing cask.
The rhum-finished release was first mentioned in a November, 2025 press release, but I didn’t see a press release talking about this bottle – even though it was released at the same time. To my knowledge, it was the first time we’d see an Experimental Series from Castle & Key using their wheated bourbon mash bill (73% corn, 10% wheat, 17% malted barley). The finishing time in those Spanish Oloroso casks was roughly the same – this time it was 17 months – but otherwise it seemed like the bourbon was much older (maybe up to 6 years old).
I’m already a fan of their wheated bourbon from both the Castle & Key brand and from the Forbidden brand – so I was eagerly anticipating that this would also be good. What did I find out? Read on. I sampled this neat in a glencairn.
Tasting Notes
Nose: Sweet winey scents are apparent on every sniff. Other fruit notes include cherries and some raisins. There is a certain oxidized note that smells like an old furniture warehouse. Most of the typical vanilla and caramel notes seem to be covered up, but there is a certain sweetness to the nose that I still think makes it work.
Palate: Even though this is under 103 proof, there seems to be quite a bit of spice with every sip. I can taste ground pepper and cinnamon – kind of in the zone of Red Hots candies. Fruit notes include oxidized cherries, grapes and figs. There is also a rancio note that seems fitting considering these Spanish Oloroso casks are probably very old.
Finish: Pleasantly long with lasting fruit and wine notes that coats everything on the way down. The bourbon underneath contributes some more to the caramel and oak, but not in a big way. The spice notes also perfectly compliment everything in the sip you just took.
Score: 7.2/10
Overall this was a well-crafted bourbon that has a good balance of cask influence and bourbon influence, but is also a tad bit on the simple side and doesn’t have a huge array of flavors. Also, the tannins are a bit lacking probably because of the age or low proof (or both). Still, I very much enjoyed what was in this bottle.
If you’re not familiar with the world of Scotch, then Sherry cask finishes probably don’t make much sense to you. Sherry has such a heavy-bodied nature about it that it can overwhelm delicate malt whiskies, but it can also ramp up the overall flavor threefold. And when we’re talking about Oloroso Sherry, it brings an extra dimension of spiciness to the equation.
But bourbon is a different story because the new charred oak influence is strong enough to fight any finishing barrel characteristics. Sometimes this results in a muddled mess of competing flavors and sometimes it results in harmony where the oak and vanilla work with the fruit and spice of the wine.
I think that Castle & Key’s experiment here was one of the better attempts at a Sherry-finished bourbon. It wasn’t too sweet and it wasn’t too spicy. At times I think it might have overwhelmed the bourbon underneath, but other times it seemed fine. I think the bourbon they used must be very delicate underneath to all all of the cask influence to shine. Luckily, these Sherry casks seem like some of the better ones I’ve tasted (although we’re not sure where they were sourced from) so I believe they were ultimately a net positive.
Final Thoughts
The MSRP for this bottle was around $60, but it’s going to be hard to find because of the limited bottle count and availability of states that it was distributed to. Not everyone will get a chance to taste it, but I will tell you that if you get the opportunity, the combination of flavor and value makes this Experimental Series worth picking up. I can’t wait to try more of them.