ABSTRACT
The coffee has spread over the Europe in the 17th century and has been imported to Japan in 1858. Th? coffee is popular as same as tea in Japan. The sales o f coffee beverage shares from 20 to 50 % o f all beverages [6]. The taste o f coffee gradually gets worse as time passes after dripping. It is difficult to keep flesh taste o f coffee for long time. The bitter taste is mainly influenced by the caffeine. Since the sour taste is influenced by various carboxylic acids which results to the hydrogen ion concentration. The pH controlling has been induced by the tourmaline[7], it is possible that the tourmaline controls the carboxylic acid concentration to keep the coffee taste for long time. Therefore, we study the influence o f the tourmaline on the sour and bitter tastes o f coffee as aging time passes.
