For most of us, the heavy rocking of a boat at sea is enough to make our stomach churn. But for barrels of Kentucky whiskey, the motion of the ocean may speed up its aging process, developing darker, richer flavors than bourbon aged the same amount of time on land.
Artisan Kentucky bourbon distiller Trey Zoeller recently told NPR’s The Salt about his experiments with ocean-aged bourbon. Five years ago, Zoeller teamed up with former high school classmate Chris Fischer, who heads OSEARCH, an organization that tracks the movements of sharks and other apex predators. Fischer agreed to carry a handful of Zoeller’s whiskey barrels aboard a research vessel traveling around the equator. The barrels spent three and a half years at sea and traversed over 10,000 nautical miles before returning home.
When Zoeller finally tapped the seafaring barrels, he told NPR that the results had “exceeded our expectations.” The whiskey contents, which had started clear, were darker than 30-year-old bourbons.
To find out what is happening to the bourbon as it gets rocked by the sea, NPR interviewed University of California chemist Tom Collins:
“Chemist Tom Collins, a researcher at the University of California, Davis, who has analyzed the flavor profiles of American whiskeys, says higher temperatures like those found in tropical locales, and the swill of the ocean, can both accelerate the whiskey aging process.
‘The daily swing in temperature matters,’ Collins explains. ‘As the liquid warms up, it expands into the wood. And then as it cools down, it contracts, which can improve extraction’ of compounds from the wood – compounds that give aged whiskey its characteristic flavor. ‘These reactions are generally favored with higher temperatures.’ ”
While Zoeller and Fischer’s experiment may seem revolutionary, the process of aging Kentucky bourbon by boat actually goes back to the very origins of the U.S. whiskey trade. During the 18th century, when trade was reliant on waterways, Kentucky distilleries would ship their whiskey along the Ohio and Mississippi rivers to buyers throughout the South, sending the barrels as far as New Orleans.
Instead of a step forward, Zoeller and his whiskey are taking several step backwards and returning the bourbon-making process to its roots. Unsurprisingly, like most wonderful things, bourbon’s roots seem to trace back to the sea.