Does anyone have solid info on how long longjing tea lasts (i.e. how long it's good for before the flavor starts to deteriorate) in a metal tea tin after it's been opened? I'm not entirely certain I got a straight answer from the folks I bought it from, who assured me that I should come back for new tea every few months and drink what I have within three months.
What kind of puzzles me is that if the shelf life is so short, how do tea sellers have fresh (or "fresh"?) tea throughout the year, when the stuff is only harvested in the spring? Do they freeze it? And if so, does it really not have any effect on the flavor to freeze the leaves? (Coffee tastes distinctly worse to me after the beans have been frozen.)
Help me clear up these mysteries, please!