The Royal Navy issued its last rum rations on July 31, 1970. Three hundred years of rum distribution, by and for British officials, ended on what came to be known as “Black Tot Day.”

Rather than waste the final rations of their stock, the Brits emptied what oak casks remained into imperial gallon stone flagons. Most of the booze—which was likely distilled in the Caribbean in the 1940s—sat untouched in a warehouse for nearly 40 years, emerging only for special occasions such as royal weddings.

Speciality Drinks, a spirits supplier, acquired the rum in time to release it on the 40th anniversary of Black Tot Day, back in 2010. They blended all the flagons together, named the new product “Black Tot Rum” and packaged the lot. About 6,000 bottles went on sale for close to $1,000 each.

Given Black Tot’s rarity, some argue that a bottle is less of a drink and more of a Royal Navy collectible item. On the spirits blog Inu A Kena, Josh Miller went so far as to muse, “Do you drink it or will it to your heirs?” Given his review, which describes the rum as tasting like black-strap molasses, dark smoke, oak, maple syrup, and possessing a “very odd undertone that is reminiscent of soy sauce,” willing it to your descendants and enjoying a more common rum might be the most strategic move.