[geeks] caffeine - differences based on source

[Sridhar Ayengar]

nate at portents.com wrote:
>> strictly speaking, tea contains little or no caffeine at all.
> 
> That doesn't agree with my understanding or experience with teas.  I think
> wikipedia probably has it right:
> 
> "Tea is another common source of caffeine. Although tea contains more
> caffeine than coffee, a typical serving contains much less, as tea is
> normally brewed much weaker. Besides strength of the brew, growing
> conditions, processing techniques and other variables also affect caffeine
> content. Certain types of tea may contain somewhat more caffeine than
> other teas. Tea contains small amounts of theobromine and slightly higher
> levels of theophylline than coffee. Preparation and many other factors
> have a significant impact on tea, and color is a very poor indicator of
> caffeine content.[19] Teas like the pale Japanese green tea gyokuro, for
> example, contain far more caffeine than much darker teas like lapsang
> souchong, which has very little."

Tea doesn't contain much caffeine.  All the assays I've ever seen that 
have measured the caffeine level as high have been measurements of the 
dry leaf.  Every analysis of the brewed drink I've ever seen has shown 
that the theophylline level is far higher than the caffeine level.

Peace...  Sridhar