Interest in the positive benefits of theanine in tea (relaxing, mind
calming and stress reducing) is long overdue, but the published
literature is woefully short of reliable data. The Tea Research
Foundation of Central Africa did recently publish some Japanese
analyses from 2003 showing quite considerable theanine variation
country to
country and tea type to tea type:

Japan, average 0.86% - range 0.2% to 1.6% (15 teas measured)
North India, average 0.91% - range 0.5% to 1.4% (4 teas)
Argentina, average 1.41% - range 1.0% to 1.8% (12 teas)
South India, average 1.48% - range 0.6% to 2.4% (4 teas)
Malawi, average 2.20% - range 1.1% to 3.4% (12 teas measured)

The theanine difference between the Assams and the Malawis - which in
blenders terms are fairly close - is particularly interesting.

I am particularly happy at the high levels of theanine in the Malawi
teas as we are pioneering use of these bushes for White Teas - two of
the cultivars we currently use for white tea production come in at
2.2% and 3.1% theanine - way above the norm in the rest of the world's
teas. We sell these as Chilwa and Salima respectively.

If anyone has any, or knows of any, other theanine content data I
would be very pleased to see it.

Nigel at Teacraft