If you forget to drink a cup of good quality Japanese green tea, it changes to a darker colour. (Presumably because it oxidises).
But if its then heated slightly, and mixed with fruit juice it is still quite drinkable.
Would it be worthwhile drinking such old tea purely for any of the *health benefits* still remaining, or would they have been substantially lost?
Maybe, but I bet there's other stuff going on in there. Try whisking it a bit and it should go darker much faster, if indeed it is oxidation going on.
Frankly, that sounds really nasty.
To answer this question, one would have to first of all know where the health benefits of tea come from.
I would claim that much of the health benefit is merely the fact that it gives you a chance to stop, find a quiet time, and concentrate on the experience of drinking tea rather than all the chaos going on around you.
If the tea tastes just "drinkable," you will miss this benefit.
Tea is really quite remarkably inexpensive. Even a high end tea is going to cost you less per cup than a barely-drinkable wine and not much more than a soda. Unless you are very, very poor there's no reason not to just make a new cup.
--scott
If tea is properly stored it should last forever. I have 20 yr old Japanese teas I still enjoy. I think the biggest enemy of oxidized tea is moisture. For fermented teas it is a blessing. Teas over exposed to moisture will go 'flat' or loose their taste. Even then you can reheat the leaves in a pan. Japanese teas are generally steamed reducing oxidation which makes them ideal for long term storage. You might see a change in leaf color but it is on the surface not within. The idea of freshness is more dependent on tea as an agricultural crop than as a product. It is better to enjoy tea for what it is. The health benefits dont cost you anything extra.
Jim
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