A tablespoon is a non-scientific but very widely used unit of volume, which works very well in cooking, herbal medicine, etc. It is represented by a capacity of one tablespoon which varies from roughly 15 mL in the US to 20 mL in Australia.
1 If tea is properly stored, it can potentially last up to a year for green and black teas. White tea lasts about six months before it isn't as good in quality as when fresher. Stale tea (or bad tea) will taste flat, as if you're drinking paper.  Glass or ceramic containers are fine provided that they're opaque.
Quick Answer. Tea has its own expiration date, like other beverages, and because of this tea can become expired, losing its natural aroma and taste as the natural oils in the tea leaves evaporate with time. When stored properly in a freezer, tea can last up to 2 years past its expiration date.