Contrary to popular belief, green tea caffeine content can be
higher than black tea. It really depends on the kind of green tea you
are drinking.
Oxidation doesn't increase caffeine content. In
fact, some studies have found that the longer tea oxidises, the lower
the caffeine content.
Colour is a poor guide to the amount of
caffeine tea contains. The finest Japanese green tea - Gyokuro -
contains more caffeine than the black Lapsang Souchong.
So what influences green tea caffeine content?
Plant Variety
Camellia sinensis has two sub varieties: the Chinese sinensis and the Indian Assamica.
The
Chinese green tea is a slow growing shrub that produces small, narrow
leaves. Usually cultivated from seeds, it has less caffeine, ranging
from 1% to 3% in dry weight.
The Indian black tea is a quick
growing tree that yields large, broad leaves. Usually cultivated using
the vegetable propagation method, it contains more caffeine, ranging
from 3% to 5% in dry weight.
It is the plant variety, not oxidation, that causes black tea to have roughly the twice the caffeine as green tea.
But not all parts of the tea plant have the same amount of caffeine.
Leaf Style
Many
high grade green teas are made from the bud and its adjacent two
leaves. These tender shoots are the sweetest, tastiest and healthiest.
They
are the richest in catechins, which contains all the antioxidants, and
the sweet and fresh tasting theanine, which calms and soothes the mind.
Unfortunately, they also contain the most caffeine.
The younger
the leaf, the more caffeine it contains. According to Upton Tea, the bud
and first leaf contain 5% caffeine in dry weight, the second leaf 3.5%,
the upper stem 2.5% and lower stem 1.4%.
It is no coincidence
that the finest green tea from China (Longjing or Dragon Well) and Japan
(Gyokuro) have one of the highest caffeine content.
Teabags have less green tea caffeine content, and a poorer favor to match.
Black
tea is made from larger, more mature leaves. This means that a high
grade loose-leaf green can have as much caffeine as black tea, sometimes
even more.
Growing and Making Conditions
Now we are in the realm of uncertainty.
The
local growing conditions can influence the green tea caffeine content.
An often quoted example is the Japanese Gyokuro, which is shaded away
from sun to preserve its theanine and caffeine content.
Other less
obvious contributing factors are soil, climate and when the tea is
harvested. Processing method, such as withering and oxidation also play a
part. The longer the leaves are left to wither, the higher the
caffeine. But the longer they are left to oxidise, the lower the
caffeine.
Now you see why depending on who you ask, green tea caffeine content can vary from 8 to 75 milligrams a cup?
Visit
Green Tea Caffeine Content for a full discussion of this abridged article.
Read
Seven Way to Drink Green Tea Without Caffeine.
Receive a
free copy of our recommended book Drinking Green Tea: Ten Frequently Asked Questions. Just sign up to our free
Amazing Green Tea Newsletter and keep up to date with tea related news!
Julian
Tai writes regularly for Amazing-Green-Tea.com, an info-site dedicated
to providing unbiased and accurate information to the art and science of
tea drinking.
Copyright © 2007 by Julian Tai. All rights reserved.
Post a Comment
Thanks for visiting my blog, please leave your comment"