Beer Analysis Using an Electronic Tongue

A taste sensor is an electronic tongue with global selectivity, which means the characteristics to decompose a chemical substance into taste qualities and to quantify each of them. It comprises several kinds of electrodes, on which a lipid/polymer membrane is pasted, and can discriminate, identify, and quantify the taste of foods or medicines. It is now commercialized, and has been applied to many kinds of foods and medicines. The composition of the membrane is designed by considering the membrane electric charge density and the hydrophobicity on the basis of physicochemical properties of taste substances. The taste is evaluated using the linear transformation of sensor output, and it provides a "scale of taste." The obtained taste pattern for beer is constructed from five axes of five basic taste qualities. A taste map expressed by 2 axes of bitterness and sourness is obtained for 40 brands of beer. These results enable us to discuss and compare taste characteristics of beer.