Gustatory discriminative norms for caffeine in normal use point to supertasters, tasters and non-tasters

Among the early indications of the existence of supertasters, tasters and non-tasters was a trimodal distribution of sensitivities to the taste of low concentrations of caffeine in water. A similar three peaks of prevalence have now been seen in the concentration of caffeine in the individual’s usual coffee drink that is perceived as the most preferred, measured by normed multiple discrimination psychophysics. Furthermore, the mode at the lowest concentrations of caffeine in coffee—the putative supertasters—was clearer for preference than for bitterness. This was because rated preference for a sample of coffee as a whole can be more sensitive to differences in level of caffeine than rating specifically how bitter it is. This criterion of gustatory performance is independent of the particular scores given by an assessor or the subjective experiencing of any sensations. Hence perception of the tastant in a familiar context is capable of picking out supertasters and non-tasters from the tasters.