Compounds from numerous chemical classes elicit bitter taste, in humans, through a receptor-mediated process involving activation of single or multiple hTAS2R taste receptors. Bitter taste perception has been measured quantitatively through numerous psychophysical methods, making comparisons between studies difficult. Such studies often use a limited set of compounds perceived as bitter to humans. Thought to be an evolutionary mechanism for toxin detection, bitterness is unpleasant, and other reports have mistaken compounds with unpleasant, non-bitter sensations as bitter, possibly due to lack of semantic descriptors available to describe such sensations. Still, however, reports from human and animal studies have suggested that, even for prototypical bitter stimuli, there may be perceivable differences between bitter compounds. Here, seventeen bitter compounds from a range of chemical classes were measured quantitatively for their taste quality and intensity using modern psychophysical scaling with the generalized labeled magnitude scale. Characterizing such a large number of compounds using a modern method helps to establish better concentration-intensity relationships than could previously be determined from prior literature. Intensity-matched concentrations of eleven food-derived bitter compounds were then evaluated qualitatively using directed free sorting in order to remove the use of language from the perceptual experience. Subsets of these eleven compounds were then compared for their similarity to six oral pharmaceutical compounds of identical intensity using a different semantic-free task called Polarized Sensory Positioning. Multidimensional scaling, multiple factor analysis, DISTATIS, and cluster analysis techniques were used to elucidate the perceptual relationships revealed through the qualitative tasks employed. Three unique clusters of predominantly bitter food-derived stimuli were found in free sorting. The first group contained quinine hydrochloride, quinine sulfate and naringin; the second contained caffeine, theobromine, and sucrose octaacetate; the third group contained a high and low concentration of L-tryptophan in addition to L-phenylalanine, tetralone, and urea. Four clusters were revealed using Polarized Sensory Positioning, where both food-derived and pharmaceutical products were compared for their taste qualities to reference stimuli. Reference stimuli, coined poles, were selected from the results of the free sorting experiment, each representing one of the three clusters. These four clusters found in Polarized Sensory Positioning were as follows: a) caffeine and L-phenylalanine, b) quinine hydrochloride, naringin, denatonium, c) sucrose octaacetate, tetralone, L-tryptophan, urea, d) acetaminophen, ranitidine, famotidine, and dextromethorphan. Notably, the pharmaceutical compounds were isolated from the other bitter stimuli in their own cluster, even though all concentrations were shown to be roughly intensity-matched. Overall, these data show that within a set of prototypical bitter exemplars, perceptual differences exist. While the methods employed do not make efforts to define the basis of these differences, these data suggest, from multiple experiments, that bitter taste may consist of distinguishable taste qualities.