Caffeine content of brewed teas (bags) (2008)

[silverneedles]

new study, if someone has full access

J Anal Toxicol. 2008 Oct;32(8 ):702-4.Links
Caffeine content of brewed teas.
Chin JM, Merves ML, Goldberger BA, Sampson-Cone A, Cone EJ.

Department of Pathology, Immunology and Laboratory Medicine, University of Florida College of Medicine, P.O. Box 100275, Gainesville, Florida 32610-0275, USA. (Sal ... can you pay them a visit )

Caffeine is the world's most popular drug and can be found in many beverages including tea. It is a psychostimulant that is widely used to enhance alertness and improve performance. This study was conducted to determine the concentration of caffeine in 20 assorted commercial tea products. The teas were brewed under a variety of conditions including different serving sizes and steep-times. Caffeine was isolated from the teas with liquid-liquid extraction and quantitated by gas chromatography with nitrogen-phosphorus detection. Caffeine concentrations in white, green, and black teas ranged from 14 to 61 mg per serving (6 or 8 oz) with no observable trend in caffeine concentration due to the variety of tea. The decaffeinated teas contained less than 12 mg of caffeine per serving, and caffeine was not detected in the herbal tea varieties. In most instances, the 6- and 8-oz serving sizes contained similar caffeine concentrations per ounce, but the steep-time affected the caffeine concentration of the tea. These findings indicate that most brewed teas contain less caffeine per serving than brewed coffee. ( <~~ genii at work with grant moneys )

PMID: 19007524 [PubMed - indexed for MEDLINE]

I think probably they're using tea bags
The no relation caffeine - variety of tea is interesting ... tho they are using tea bags ... i mean sheesh , what respectable human drinks tea bags

[gingkoseto]

These findings indicate that most brewed teas contain less caffeine per serving than brewed coffee. ( <~~ genii at work with grant moneys )

I am surprised this is a newly published article. Now I am really curious if they used some innovative, high tech methods to get this result

[Pentox]

What the crap. How did this get published? Seriously this thing smells at best a senior project. It's just doing a crapton of extractions and running it through a GC. If these guys had grant money for this, WTF.

[Wesli]

It could have been paid for by the company that sells the tea, who allowed them to publish.

[silverneedles]

... science at its best, only in the "J Anal Toxicol."

[gingkoseto]

What the crap. How did this get published? Seriously this thing smells at best a senior project. It's just doing a crapton of extractions and running it through a GC. If these guys had grant money for this, WTF.

Yeah! I remember reading about senior project about caffeine contents in different teas. They didn't have gas chromatography kind of equipment, but they even thought of comparing steeping time, with and without shaking the container... A good senior project.

Seeing this makes me think publishing is easy. But how come it seems hard for everyone else to publish a journal article

[AlexZorach]

This is a kind of old thread but I recently used this article mentioned, and a second, older (2005) article, as sources to write a more general-audience article on caffeine in tea, in case anyone is interested.

Before you all are quick to belittle these studies and articles, I want to point out that:

1. They're the best that is out there.
2. They allow you to draw some valuable conclusions to clear up misconceptions about caffeine content.

The gist of it is that caffeine content varies more from one tea to the next than it does between big categories such as green tea, black tea, oolong tea, etc.

There's a lot of misinformation out there, especially in tea companies' material...claims about low caffeine content of green or white tea (which is not true). While these studies are only a beginning, they're at least SOMETHING we can cite if someone makes a bold (and incorrect) claim about caffeine content of various types of teas.

I'd view these studies as a good starting point...and I hope people continue to delve into more depth.

Also...I'd appreciate some feedback/criticism of my article, in case anyone would like to share any! Thanks!