“It was purely experimental,” Macleod recalls of her work with those wine barrels. “We just wanted to see what those casks would do to the whisky. There was no real thought that we would release them, although there was that hope.”

In particular, Macleod still remembers filling a red wine cask, then checking on the liquid’s evolution one month later, where—in horror—she discovered that the already-mature whisky had turned pink. “That was a heart-stopping moment for me,” she says, sighing in a way that suggests she can still feel the panic that washed over her so many years ago.

As the months went by, however, Macleod and her team watched as the blended whisky’s hue gradually shifted from pink to orange, before eventually returning to the customary color that a well-aged whisky is expected to have. “That was a learning moment,” she adds with a smile.

Since then, Macleod and her team have boldly experimented with other barrel finishes. Some have blossomed into beautiful creations showcasing Port wine, Calvados, and Caribbean rum. Others have proven to be more challenging to work with, but that hasn’t deterred the Dewar’s team from venturing forward, always willing to try something different.

Despite its enthusiasm to take risks, Dewar’s, like all Scotch whisky producers, must adhere to certain parameters set by Scotch Whisky Association. “We’re protected by the Scotch whisky regulations, so we have to keep within the confines of oak,” Macleod acknowledges. “But,” she adds, “there are so many different species of oak that we can draw from.”

More than five years ago, for example, the brand paid handsomely for a shipment of Mizunara casks from Japan, which have already paid dividends with the brand’s 8 Year Old Japanese Smooth and 21 Year Old Mizunara Cask. Currently, Macleod is overseeing experimentation with Scottish oak, which can be challenging, she says, given the wood’s porosity and its ability to impart too much wood character. She and her team are also keeping tabs on whiskies maturing in barrels made from a species of oak that grows around the Black Sea.

As for what’s new and available for purchase, Dewar’s has recently released its Double Double 21-Year-Old Stone Toasted series, which features a smattering of whiskies that are finished in either American or French oak casks that have been toasted using magma stones or pieces of jade heated to intense temperatures. “It allows the whisky to really talk to the wood,” Macleod says of the toasting process. “You get all the richness of the wood without any smoky notes coming through.”

While she acknowledges that the brand had never done anything like it before, the team was confident that the Double Double range would be a perfect vessel to showcase the uniqueness of those barrels. The Stone Toasted expression currently available on U.S. shelves—a whisky finished in Icelandic magma stone–toasted French oak—affirms the team’s instincts. The spirit delivers complexity wrapped in an elegant package, offering notes of cinnamon, cloves, creamy caramel, baked apples, and toasted cereal. It’s fascinating, refined, and truly one of one.

“It’s more than just a new finish,” Brian Cox, the vice president of Dewar’s North America, says of the Stone Toasted series. “It’s a celebration of craftsmanship, discovery, and the evolving art of cask maturation. By introducing something new and different to the category, we’re offering whisky lovers and newcomers alike a new way to discover rich layers of flavor shaped by time, tradition, and experimentation.”

In regards to the brand’s innovation-focused modus operandi, Macleod is quick to point out that she and her team aren’t fixated on the prospect of innovating just for innovation’s sake. “We are guided by a real sense of purpose,” she explains. More specifically, she points to a famous quote from composer Gustav Mahler: “Tradition is not the worship of ashes, but the preservation of fire.”

“That is exactly what we grapple with at Dewar’s,” says Macleod. “Next year, Dewar’s will be 180 years old. We’ve got this rich, storied legacy of whisky making, but we have to be careful that we still remain relevant to our whisky drinkers of today and our whisky drinkers of tomorrow.

“It’s about respecting traditions and our flavor profile that’s been developed and loved,” she continues, “but making sure that we’re not ignoring new techniques that might help us take our whisky forward to the next generation.”

This article was produced in partnership with Dewar’s.