Because so many people approach tea from a health perspective, there is a huge volume of marketing information out there, much of it nonsense.
One of the more persistent myths I've come across is this:
"90% of all the caffeine comes out of tea in the first 30 seconds of steeping. You can naturally decaffeinate by pouring off the water after the first 30 seconds and resteeping the leaves."
Nope, false. The Web site, Wonder of Tea, deals with this myth here:
Tea Caffeine Legend #3
You can have a decaf cup of tea by pouring out the first infusion after steeping for about 30 seconds
When you pour out the first infusion after 30 seconds, you remove some of the caffeine but not all so it’s wrong to label this “decaffeinated “.
According to a study done by Hicks et all published in 1996 in Food Research International, steeping a tea for 15 minutes and then flushing it out removes 100% of the caffeine. Personally, I think that will also take away most of the flavour of the brew. Experiments have shown that steeping for about 5 minutes works quite well in retaining the flavour and that removes about 70% of the caffeine.
The data from their finding extrapolated below shows the caffeine extraction percentages within the 5 minutes period. Steeping for:
30 seconds – 9%
1 minute – 18 %
2 minutes - 34%
3 minutes - 48%
4 minutes- 60%
5 minutes - 69%
10 minutes - 92%
15 minutes - 100%
In other words, you can remove 100% of the caffeine in the tea after 15 minutes of steeping. Now, I don't have access to the study, so I can't verify the number of tests, how the caffeine was measured, nor what temperature the leaves were steeped at. But even so, it's pretty clear that the myth is busted.
For an even more in-depth look at caffeine and tea, go here:
[This is a repost from 7/28/09, and it's been one of my most-read articles. People must be very concerned about their caffeine intake!]