The creator of elderflower liqueur St-Germain, Robert J. Cooper, died on Monday at the age of 39. Officials at the Cooper Spirits Company confirmed Cooper’s death on Wednesday. The New York Times reports that the cause of his death has not been verified. Cooper sold the drink—which at one point earned the nickname “bartender’s ketchup”—to Bacardi in 2012, earning “more than I expected to see in a lifetime” from the deal. The sum of the agreement was never disclosed.