Review: Boulder Spirits Single Malts and Bourbons 5 Years Old

Review: Boulder Spirits Single Malts and Bourbons 5 Years Old

Boulder Spirits — based, well, see if you can guess — produces a range of whiskeys, including at least eight bottlings primarily running to single malt and bourbon. Its whiskey continues to age in the Colorado climate, and recently Boulder hit a new milestone, with several whiskeys in barrel at 5 years of age.

We recently received samples of its five year old single malts (at two different proofs) and a bonded bourbon (also at two different proofs). While these are not yet commercially available, our preliminary thoughts are. Let’s taste.

Boulder Spirits American Single Malt 5 Years Old 100 Proof – An instructive look at what virgin oak can do to a delicate single malt. Immediately heavy and woody on the nose, the whiskey is overwhelmed by tannin — but also finds a radically different counterpoint in the form of ultra-sweet butterscotch and spun sugar. The palate has even more going on, that butterscotch note becoming even sweeter and a bit cloying as it develops, paired with a surfeit of baking spices. It’s almost enough to keep the overpowering barrel character in check, but not quite, as the finish remains tannic, almost astringent. Tough going at times. B- / $NA

Boulder Spirits American Single Malt 5 Years Old 136.5 Proof – At (presumably) cask strength, Boulder’s single malt becomes a more engaging beast, driven by a substantial heat that sharpens the experience, tempers the wood, and provides a bold clove note. It’s still quite sweet from that butterscotch note, but here it’s less overbearing. The palate continues the scorching theme, with the wood and sugary notes showing more modestly here. There’s ample spice in attendance — so much so that the whiskey doesn’t immediately connote single malt — but it fades enough en route to a creamy and chewy finish that offers notes of graham cracker pie crust. It’s still rough around the edges, but it’s much more cohesive and engaging than the 100 proof, to be sure. B+ / $NA

Boulder Spirits Bourbon Bottled-in-Bond 5 Years Old 100 Proof – Initially funky and a little vegetal on the nose, with a ton of pepper in the mix. Time in glass helps some of the more aggressive elements blow off, but this remains a pungent, powerful aromatic experience for quite a while. The palate offers more of a sedate, traditional bourbon character, warmer than the 50% abv would suggest but not overdone, a corn-heavy experience that folds in elements of peanut shells, brown sugar, and a brown butter, all in a creamy swirl. The finish tempers the heat and lets that caramel corn character shine. Straightforward stuff, but a step above what we see from most craft distilleries these days. 100 proof. B+ / $NA

Boulder Spirits Bourbon 5 Years Old 129.5 Proof – Similar to the 100 proof, but naturally quite a bit hotter and more aggressive. Sharp barrel char notes lead the way on the nose, with a hefty, peanut-and-popcorn character dominating the palate. Brown sugary, vanilla-dusted sweetness is here, but layered beneath ample notes of cinnamon and cayenne. That peanut character keeps kicking well into the finish, with a hint of dill lingering behind. Unlike the 100 proof expression, this is racy, never creamy, and the heat never fades at all. Again, there’s nothing shocking in the mix, but it remains on point — and a solid example of high-test craft bourbon. 129.5 proof. B+ / $NA

Boulder Spirits American Single Malt 5 Years Old 100 Proof




Christopher Null is the founder and editor in chief of Drinkhacker. A veteran writer and journalist, he also operates Null Media, a bespoke content creation company.


  1. JDub on April 14, 2022 at 11:33 am

    The fourth sample, high test bourbon, I thought bottled-in-bond was required to be 100 proof?

    • Christopher Null on April 14, 2022 at 2:23 pm

      Good catch. That’s a copy and paste error. It is not technically bonded. Correcting the review now.

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