Bring your tea back from the dead.
If you’ve found yourself with a stock pile of aging Japanese tea, don’t throw it out yet. You can revitalize it a bit by doing a simple re-roast. Sencha is fired during processing to lower moisture levels and add a certain Kaori, or aroma. When tea is introduced to a heated surface essential substances, compounds and dry matter release their aroma. Refiring can heighten some of the aromas that have been lost due to aging (contact to air and light). The final result depends on a lot of factors: how high the heat, how old the tea, and original quality of the leaf. I recommend dry heating a cooking skillet and spreading a small amount of tea across the surface. Make sure to continually move the tea around so it doesn’t burn: too much heat or time and you’ll end up with Houjicha (you could also make that your goal). Keep a medium flame and pay attention to the smell of the tea as you go. You’ll notice a meady aroma and perhaps something nutty. At this point take the tea and spread out on a cool plate. Allow it a bit of time to cool, then enjoy. Obviously teas that had more flavor to begin with will find more benefit in this. Re-fire right before you intend to drink the tea. Have fun and if you burn the tea, just throw it out and try again.