Colorado-based Stranahan’s celebrated their 20th anniversary in 2024, and today, the Denver distillery is one of the oldest producers of American Single Malt. (A category of spirit that was recognized by the federal government this past January.) While the distillery is known for a wide variety of specialty releases and cask finishes, one of its latest bottles pays homage to its origins and Colorado’s storied brewing culture.
Fortunately for whiskey drinkers, this is one collaboration where the beer enhances the drinking experience instead of overpowering it.
All Stranahan’s single malt initially ages in new charred American oak barrels. After an initial aging period, often between four and six years, some of that whiskey is transferred to a variety of other casks for extended finishing. As someone who has seen their operation up close, the distillery’s deep stocks feature a dizzying array of finishing casks, including barrels that previously held a broad diversity of wines, as well as spirits including mezcal, rum, peated Scotch, and more.
To focus in on a single type of secondary barrel aging, Diamond Peak is Stranahan’s annual, nationwide bottling that highlights “one specific variety of speciality cask-finished whiskies.” The 2025 version of Diamond Peak—the fourth edition overall—is titled “Local Brewer’s Cask.”
To create the expression, Stranahan’s lent their used American single malt casks to four Denver-area breweries. Local beer was aged in those barrels, after which they were dumped and returned to Stranahan’s (or “boomeranged” according an evocatively worded press release). Those barrels were then refilled with Stranahan’s single malt, which aged for an additional period of between one and one-and-a-half years, depending on the barrel.
The liquid in those final barrels was blended to create this year’s Diamond Peak release. Previous versions of Diamond Peak featured whiskey that underwent additional aging in casks that once held Bushmills, extra añejo tequila, and Caribbean rum. (Bushmills and Stranahan’s are both owned by Proximo Spirits.)
But this latest, beer-influenced Diamond Peak gets extra points due to the nostalgia factor. In fact, the first version of what would become Stranahan’s single malt was distilled from beer mash made by Colorado’s Flying Dog Brewery. Stranahan’s has long maintained relationships and collaborated with local breweries on a variety of projects.
But the proof is ultimately in the taste. So how does this latest Diamond Peak stack up?
The nose starts off with some classic scents familiar to longtime Stranahan’s drinkers: dried orange peel, candied ginger, rum raisin ice cream, fresh drip coffee, and heavily spiced fruitcake. At least based on aroma, it’s a little funkier and more intensely spiced than some other recent expressions from the distillery—but it’s certainly not overpoweringly hoppy or otherwise tilted more toward beer than the base whiskey. (A trough some beer barrel-finished American whiskeys can easily fall into, for better or for worse.)
The palate leads with some light tropical fruit—fresh pineapple, ripe papaya—with some tannins in the realm of cigar box and fermented tea leaves. Birch and cedar build mildly at the midpalate, along with mulberries and a touch of hard apple cider. The flavor is quite pronounced for 90 proof (frankly a bit more than I was expecting), which leads to a balanced finish that once again leans into a variety of fruits with enough oak to cut through the sweetness.
This latest iteration of Stranahan’s Diamond Peak is now available at the distillery for $79.99 and at select retailers (where prices may vary).