The generally recognised English term for this taste ascribed to L-
theanine in Japanese green tea is "brothy", though before we
discovered what the Japanese called it we used "maritime" to describe
its distinct savoriness. Raw tuna or sushi quality is close to it.
This taste in general is known as "umami" and recently has been added
to the four classic gustatory (taste) sensations (sweet, salt, acid &
bitter), along with metallic. Astringent is not considered a taste
(except by tea tasters) as it is considered strictly to be a tactile
stimulus - of loss in slickness of the buccal mucosa. Nor yet is
"fresh" a taste, although (and particularly to a tea enthusiast) it is
an essential component and in teaman's parlance could be termed
"alive" or (for black teas at least) "point".

Nigel at Teacraft