"Nigel" > wrote in message
...
> On Dec 8, 5:43 pm, "Bluesea" > wrote:
>
> > So, now I'm in the position of wondering if the myth about DIY
> > decaffeinating is a myth since apparently anybody can put up a webpage
with
> > the scientific basis for whatever's being touted.
> >
>
> As an antidote to the wishful thinking about the decaffeinating
> effectiveness of a 30 second wash I proposed the data presented in
> "Tea preparation and its influence on methylxanthine concentration" by
> Monique Hicks, Peggy Hsieh and Leonard Bell which was published in
> 1996 in Food Research International. Vol 29, Nos 3-4, pp. 325-330.
> Hicks et al measured the caffeine and theobromine (total
> methylxanthine) content of six different teas (three bagged and three
> loose leaf, including black, oolong and green types). They measured
> caffeine extraction in boiling water at 5 minutes (69%), 10 minutes
> (92%) and 15 minutes (100%). They replicated all their extractions
> three times to eliminate error.

Another thing is that the 69% at 5 minutes is artificially low because they
included herbal tisanes in the overall average. From the abstract at
http://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."

Why in the world they included herbals, I have no idea, but if they are
tossed out as they should be simply because they're not from any Camillia si
nensis, the overall average percentages go up for the amount of caffeine
released.


--
~~Bluesea~~
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