We usually enjoy the change of taste through repeated brewing of the same tea leaves. This procedure is hereinafter referred to as "repeating infusions". Many of you might have experienced that umami flavor is getting milder as the number of infusion goes along. What about the caffeine? Does it get milder in the second brewing as well?
Incidentally, the level of Amino acid (umami) on the second infusion will get only about 60% of the first infusion. (The condition is the same as the following test) My previous entry didn’t mention anything about repeating infusions. Practically speaking, I think we need to consider about them. I have a good data from my Japanese Tea Adviser textbook, as follows:
Leaf (sencha): 6g,
First brewing: 70C/158F 170ml 90sec,
Second-Fifth brewing: 90C/194F 170ml 10sec
Japanese Tea Adviser Koza, Japanese Tea Instructor Association, 2009
How do you interpret this data? I was kind of surprised with the high level of caffeine on the first few infusions. Even though the level gradually decreases from the third infusion, the first and second are almost the same, and the third still has about 80% of the first. This is higher than I originally imagined. I’ll remember this information for my daily tea, and it will be useful.
I just want you to be aware that the caffeine level will very much differ by brewing conditions. Why do I say that? Do you remember the caffeine level on the previous entry? 44mg (first infusion on Today’s data) is much higher than 20mg of the previous one. 44mg is even higher than 30mg of black tea. I think you need to refer to these data as a rough guide for your tea.