A new study from researchers at Chuo University in Tokyo suggests that the sense of touch can significantly influence the perception of coffee's taste. Published in the journal Multisensory Research, the study found that blindfolded participants rated coffee as less acidic when experiencing smooth tactile sensations compared to rough ones, even when the source of the texture was not the cup itself.
The research involved a series of experiments designed to isolate the effect of touch. In one test, 92 participants drank black coffee from cups fitted with either a smooth kraft paper sleeve or a rough sandpaper sleeve. The results showed that individuals who drank from the rough-sleeved cup first perceived the coffee from the subsequent smooth-sleeved cup as being less acidic. This effect was not observed when the order was reversed, suggesting a specific directional influence of the rough-to-smooth transition.
Further experiments confirmed that the tactile cue did not need to originate from the cup. The effect on perceived acidity was replicated when participants touched a separate rough or smooth object with their free hand while drinking. However, the study noted that the tactile and gustatory stimuli must be simultaneous for the effect to occur. This adds to a growing body of evidence that sensory perception is cross-modal, implying that the entire tasting environment—from the texture of a cupping table to a café menu—could play a role in shaping the final flavor experience.