The technique of free-choice profiling was applied in order to characterize the sensory properties of some common organic and inorganic acids. Analysis of panelists' scores by generalized Procrustes Analysis (GPA) provided information on the relationships among samples and assessors for both the consensus and individual configurations. Results indicated that on a weight basis (w/v or v/v), acids differed in their flavor and taste dynamics. Acids were described differently by individual panelists. The GPA resulted in three important principal axes (PA). The first PA had astringency/mouthfeel as the most important factor, while bitterness and sourness were the most important for the second and the third PAs, respectively. At 0.08% (w/v or v/v), the inorganic acids, hydrochloric and phosphoric, were more astringent than sour. The bitterness of succinic (S) was intense as was the sourness of fumaric, malic and the combinations of fumaric:malic (FM), citric:malic (CM) and citric:fumaric (CF). The sensory characteristics of adipic and quinic were perceived to be very weak at this concentration. The relationship between astringency and pH was more evident than was the relationship between pH and sourness.