I have found that most sites recommend brewing a large number of small batches of tea, with multiple infusions of the same leaves, instead of brewing a large container using the same tea leaves. They point out that the desirable flavors diffuse first, so multiple infusions lets you taste them without the tanins taking over.
Why is it that multiple infusions changes the curve? I would expect that, on a second infusion, the tea leaves would pick up where they left off, so the combination of two infusions would be the same as doing one infusion for longer. Why is this not the case?