[geeks] caffeine - differences based on source

[nate at portents.com]

> 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."

And if for some reason you don't trust the wikipedia article on caffeine,
I'd refer you to page 438 of "Remington: The Science and Practice of
Pharmacy" by David B. Troy, University of the Sciences in Philadelphia,
Joseph Price Remington, Paul Beringer, published by Lippincott Williams &
Wilkins, 2005:

"A significant quantity of caffeine is present in tea and coffee and is
responsible for their CNS stimulatory and diuretic effects."

> it has theophylline, a structurally similar compound with similar but
> slightly different effects, less on the cardiovascular system but more
> on the cardiopulmonary.  remember the folk wisdom about drinking tea
> when you have a cold?  theophylline has been prescribed as a mild
> bronchodilator.
>
> on most food chemical tests, theophylline will read as caffeine.  this
> also goes for theobromine in cocoa, structurally similar as well.

Are you sure that theophylline "reads" as caffeine?  (Maybe it just forms
an insoluble complex with it?)

- Nate