To determine the caffeine concentration in tea infusion was chosen an infusion time of
5, 10 or 15 minutes. From literature data it is known that for a time of 0.5 to 15 minute
infusion the caffeine concentration increases rapidly while for 15-60 minutes the
concentration of caffeine increases very slowly. When boiling water is added over the
tea leaves, caffeine diffusion occurs in a rapid manner because there is no caffeine in
water. When leaves are infused over a long period of time, caffeine concentration
becomes higher and therefore closer to the final concentration and caffeine delivering to
a lower percentage.
In conclusion (see Figures 2-3), the caffeine concentration in the tea samples was
influenced by the infusion time. It was observed an increase of caffeine concentration
directly proportion with infusion time.