Height Matters: How Elevation Affects the Aging of Liquor

Tending the mash at Milk & Honey Distillery / Photo by Shay Yehezkel
Tending the mash at Milk & Honey Distillery / Photo by Shay Yehezkel

The Dead Sea, a salt-laden lake that borders Israel, Jordan and the West Bank, has the lowest land elevation on earth, sitting about 1,385 feet below sea level. You can’t get any lower without sinking into the ocean. It’s here that Tel Aviv-based Milk & Honey Distillery is experimenting with the impact of low elevation on aging whiskey.

“Extreme geography is our advantage,” says Milk & Honey Head Distiller Tomer Goren. “We are trying to play with this playground.”

Loosely defined as representing a sense of place, terroir has become part of the spirits producer’s tool kit, with greater attention paid to where raw ingredients are grown and barreled spirits are aged. Yet, elevation typically hasn’t been given much attention. That may change as a growing number of producers experiment with the effects of extreme altitudes—both high and low—to create spirits.

Metal barrel thief being used to pour whiskey from a barrel into a glass for tasting
Barrel samples at Milk & Honey Distillery / Photo courtesy Milk & Honey Distillery

The impact can be particularly pronounced when it comes to barrel aging, pros say.

“There’s a lot of mystery and magic to barrel aging in general,” says Karen Hoskin, founder and owner of Montanya Distillers, which makes rum in the Colorado mountains at 8,800 feet above sea level. “For me, being at high elevation, one of the things that impacts how the flavor profile develops in a barrel has to do with the penetration of the liquid into the wood.”

However, she quickly notes, sheer elevation doesn’t do the job alone. It also impacts temperature, barometric pressure and humidity.

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“For Montanya, the biggest effect was temperature fluctuation,” says Hoskin. Her Colorado rackhouse can change 20°F from day to night, in addition to wider temperature swings between summer and winter.

The pores of the wood expand and contract with heat and cold, pulling the rum in and out of the oak and giving it more contact with the barrel, which helps flavors to develop more quickly. This kinetic action is a form of dynamic aging, Hoskin explains. Some spirits makers try to mimic the effect by agitating barrels to increase contact between the liquid and the wood.

Karen Hoskin, founder/owner, Montanya Distillers (left), with Renee Newton, distiller and distillery manager / Photo by Nathan Bilow
Karen Hoskin, founder/owner, Montanya Distillers (left), with Renee Newton, distiller and distillery manager / Photo by Nathan Bilow

This doesn’t happen as frequently with rum counterparts in the Caribbean, where temperatures tend to be more stable. 

“Sometimes, at sea level, you put rum into a barrel and you and absorb a certain amount of rum into the barrel, and doesn’t change after that,” says Hoskin. “There’s not a lot of kinetic action.”

Different temperatures, humidity and climate variations like proximity to the ocean can produce different secretions from the oak, she adds, and that can also affect the flavor of a finished spirit. For example, her barrels produce sweeter notes associated with vanillin and sucrose, while the same barrels in the Caribbean might provide fruitier tones.

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Elevation can also impact the strength of a spirit. “At my elevation, I’m primarily evaporating water, so the alcohol concentration in my barrels is going up,” says Hoskin. In a more humid sea-level environment, what evaporates may be primarily ethanol, which in turn lowers the proof. “You’re just losing your booze to the evaporation,” she says.

Grain silos in the mountains at WhistlePig
A critical step at WhistlePig’s grain-to-glass process, the silos provide the perfect environment for the grain to cure, which helps ensure a consistent and high quality mash / Photo courtesy WhistlePig

Elsewhere, curiosity about the impact of aging whiskey in different climates and elevations led WhistlePig Distiller Mitchael Mahar and Blender Meghan Ireland to chart a cross-country trip to produce the Vermont-based distillery’s rye whiskey.

They filled 80 used barrels from Jordan Winery with rye whiskey, which were then driven along Route 66, through the deserts of Arizona, to reach southern California. There, the whiskey was transferred into barrels that previously held Firestone Walker beer, and driven back through flatlands and Colorado Rockies, and finally returned to Vermont.

Meghan Ireland, blender at WhistlePig, measuring an aged whiskey sample for blending into a future expression / Photo courtesy WhistlePig

While it’s difficult to isolate the effect of elevation on the finished “road trip whiskey,” the resulting rye was particularly fruity and bright, with hints of baked pear, almond and spice.

“With Roadstock, we knew there would be a lot of factors in the barrel aging,” says Ireland. “In the truck, it was shaken up a lot. But there were also altitude changes: you go through higher altitude, drier climates, and that affects how the whiskey can move in and out of the barrel. And then we had huge temperature differences driving from Vermont to California and back.”

So far, there haven’t been many side-by-side studies on how altitude affects spirits, Ireland says. It’s still a largely experimental concept.

Looking down wood-lined hallway into WhistlePig distillery barn
Barn and still at WhistlePig Distillery in Shoreham, VT / Photo courtesy WhistlePig

This is what makes empirical evidence found by producers like Milk & Honey so exciting. A new release called Apex Dead Sea is an intense, umami-laced version of their flagship single malt that’s been aged on a hotel rooftop, nestled on the arid desert coast of the Dead Sea. The distillery is also working with “comparative casks,” or single malts that are identical except for where they have aged.

The casks won’t be sold commercially but were made to illustrate how the same whiskey aged at the distillery’s Tel Aviv facility, 16 feet above sea level, compares to the Dead Sea project, aged at 1,385 feet below sea level. The difference between the two is easily apparent: the Dead Sea-aged version is notably darker and murkier, the flavor less honeyed, with an herbaceous quality and more pronounced oak notes and muted spice tones.

Further elevation-centric terroir experiments are on the horizon, too.

“It’s an exploration of places,” says Goren. “I look forward to continuing our geographical experiments, with the Sea of Galilee and the Jerusalem Mountains coming up next.”

Published on December 28, 2021