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| Tea (rec.drink.tea) Discussion relating to tea, the world's second most consumed beverage (after water), made by infusing or boiling the leaves of the tea plant (C. sinensis or close relatives) in water. |
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How can you tell if tea has caffeine?
ADDENDUM Should read "Two minutes . . .64%" > > Subsequent to that posting I rediscovered a paper by Professor Michael > Spiro whose group did some ground breaking physical chemistry on tea. > In "Tea and the rate of its infusion" Chemistry in New Zealand, 1981, > pp172-174, they disclose caffeine concentration diffusing into water > (4g loose leaf - it will have been CTC small fannings type - in 200 ml > water held at constant 80 deg C, and stirred with a magnetic > stirrer). First data point is at 90 seconds and shows 49% caffeine > removed from leaf (i.e. into water). Extrapolating from Spiro's plot > gives: > 30 seconds 20% > 1 minute 33% > 2 minutes 34% > 3 minutes 76% > 4 minutes 85% > 5 minutes 88% > 10 minutes 99% > 15 minutes 100% > Thus while a 30 second "wash" under Spiro's rather extreme laboratory > conditions (small leaf, loose in the "pot" rather than teabag, at > constant temperature and stirred vigorously) leached 20% caffeine > rather than just 9% under Hick's more normal steeping, neither of > these findings anywhere near match the 80% decaffeination claims of > the wishful thinkers perpetuated as an Internet Myth. > > Nigel at Teacraft |
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