> Another thing is that the 69% at 5 minutes is artificially low because they
> included herbal tisanes in the overall average. From the abstract athttp://cat.inist.fr/?aModele=afficheN&cpsidt=2477703:
>
> "In this study, methylxanthine (caffeine, theobromine, and theophylline)
> contents in three brews of four types of tea (black, oolong, green, and
> herbal) in both bags and loose leaf forms were investigated to determine the
> actual amount of methylxanthines present in tea as a function of different
> brewing methods...Caffeine and theobromine were not detected in either
> herbal tea samples, and theophylline was not detected in any tea tested. The
> overall average caffeine released in the first through third brews were 69%,
> 23%, and 8%, respectively."

Actually, they did not include herbals in those percentages. The teas
used to calculate those averages are Lipton black tea bag, loose black
leaves, two loose Formosa oolongs, Lipton green tea bag, and loose
green leaves.

-Brent