Multiple tea infusions and caffeine concentration I have read conflicting things about the volatility and solubility of caffeine, and at what point during the tea brewing process caffeine is released.

When tea is used for multiple infusions, such as in Gongfu style brewing, do the different infusions have different amounts of caffeine?
This study specifically addresses the question regarding multiple infusions:


  Results for all kinds of tea samples showed that the second tea
  infusion contained the highest contents of caffeine, catechins, and
  gallic acid when bag teas were steeped in 70°C water.  It was different
  from that steeped at 85 and 100°C, the highest contents existed in the
  first infusion.  These compounds decreased gradually in later
  infusions.


The paper measured 8 successive infusions on a variety of teas.  You can see how caffeine content varied exactly in their data.