Infusing 4.5 gram of tea in my 5 oz kyusu (about 150 mL water) with water at 160 degrees, after 30" the first is light and sweet and vegetal; the second (15") is sweet, a bit heavier with some sweet vegetal flavor and a bit of vanilla, a touch of umami but not much (a 30" second infusion was too heavy bodied when I tried that yesterday), and the third infusion (again 30") is more like the second, but the astringency starts to increase a little, but not enough to interfere with my enjoyment of the sweet vegetal flavors.
Delicious.
I think that shorter 2nd infusion allows the elements that have already started to leak from the wet leaves to be recovered without too much more coming out of the leaves (which would result in in an infusion strongly biased towards the umami, too much so for my taste), and then the 3rd infusion, there is not so much rushing out into the water, so an infusion the length of the first works fine.
