Some discrepancy exists on the exact date when Morris created the popular cocktail. Mixologist Dale DeGroff asserts the drink was invented in 1915, but other sources argue this happened in the 1920s. The Chilean web newspaper "El Mercurio Online" specifically contends historians attribute the year of the drink's invention as 1922, adding that "one night Morris surprised his friends with a new drink he called "pisco sour", a formula which mixes the Peruvian "pisco" with the American "sour"" (in Spanish: ""Una noche Morris sorprendió a sus amigos con una nueva bebida a la que llamó pisco sour, una fórmula que funde lo peruano del pisco con el 'sour' estadounidense."").