Relationship between Taste and Concentrations of Caffeine and Tannin in Tea Infusion

In order to discover the correlation between the concentration of caffeine and tannin released by brewing tea and the result of the palatability, as for gyokuro, sencha, mizudasisencha, hojicha, bancha, oOlong-tea, we brewed each tea three times and measured the amounts of caffeine and tannin in each different brewing period. 1. Gyokuro; The second infusion exuded more caffeine and tannin when it was steeped for 0.5, 1, 2, 3 minutes. And the first infusion exuded more when it was steeped 4 minutes. But in the palatability of each brewing tea there were little differences on the degree of bitterness and astringency. The total taste of the first infusion was the strongest and most preferred. 2. Sencha; The second infusion exuded the most caffeine and tannin when it was steeped for 0.5, 1 minute. The first infusion exuded them most when it was steeped for 3 or 4 minutes. The bitterness and astringency in the first infusion were as mush as the second infusion and in the third infusion were weaker. The more the tea was rebrewed the weaker the taste got. 3. Hojicha, bancha; The first infusion exuded more caffeine and tannin (except 0.5, 1 minutes steeped one), and the bitterness and astringency were stronger. 4. Oolong-tea; As for the concentration of caffeine and tannin the result was the same as hojicha, bancha. The first infusion with the strongest total taste was not preferred. The second one seemed to be favoured. 5. The lower quality teas have a positive correlation between the concentration of caffeine and tannin and bitterness, astringency, umami and popularity. Their tastes seem to be more affected by the concentration of caffeine and tannin. Oolong-tea has a negative correlation between the popularity and the concentration of caffeine and tannin.