The chocolate was the same in all the samples, but the volunteers found that the flavor was better when the drink was served in the orange or cream-colored cups.
"The color of the container where food and drink are served can enhance some attributes like taste and aroma," Betina Piqueras-Fiszman of the Polytechnic University of Valencia said in a press release.
The findings could be beneficial to chefs and food manufacturers, Piqueras-Fiszman added.
Previous research has found that yellow containers boost the perception of flavor of lemons in soft drinks; beverages with cold colors, like blue, seem more thirst-quenching than warm colors like red; and if drinks are pink, they are perceived as being more sugary.
The study appears in a specialist publication, the Journal of Sensory Studies.