A method to differentiate taste compounds based on their electrochemical nonlinearity is proposed. We have quantitatively estimated the electrochemical nonlinearity of surfactant solutions by using the system-identification. Electrochemical nonlinearity is influenced by the addition of various chemical species such as NaCl, HCl, and Quinine-Hydrochloride. Electrochemical nonlinearity shows similar characteristics to the same category of taste and shows a concentration dependency. It is shown that the taste sensing system proposed in the present work is able to distinguish the kind of taste and to estimate quantitatively its concentration.