For a local rum distiller in the Cayman Islands, the area’s reputation as a diving hot spot extends well beyond seeing plentiful marine life.

Unlike other rum manufacturers, Grand Cayman’s Seven Fathoms Distillery ages its fermented sugarcane and molasses in wooden barrels located seven fathoms (42ft/13m) underwater. The craft micro-distillery’s co-founder, Walker Romanica, got the idea for this unusual process after reading a biography of the Bacardi family. In the 1700s and 1800s, the Bacardi rum company attributed their numerous awards to the fact that the distillery was located near railway tracks. The constant rattling of the barrels kept exposing the liquor to different parts of the wood, for a more even distribution of barrel molecules throughout the spirit.

Romanica believes that under the sea there is a unique humidity, pressure and temperature profile that’s impossible to replicate on land. The constant push and pull of the waves does the traditional distiller’s job of rotating the barrels. Ever since one of the company’s first barrels was discovered (and returned safely), the company has kept the underwater aging location top secret.

Despite a West Indian history immersed in the rum trade, the Seven Fathoms Distillery produces the only spirit made entirely in the Cayman Islands. The rum goes down smooth and dry, and features distinct sugarcane and citrus notes and earthy, oaky vanilla flavours. (It’s meant for sipping, not shooting.) About 200 people a week take the Seven Fathoms Distillery tour, offered from Monday to Saturday, which includes a rum tasting and a walk-through of the refining, aging and blending process.

The spirit can be ordered at Binny’s in the US or the Whisky Exchange in the UK.