Matcha is very delicate stuff. Remember the movie, Gremlins? It’s pretty similar. It doesn’t like heat, air, moisture or light (and definitely don’t feed it past midnight!) Once the tencha leaves are ground, the clock starts ticking. Matcha lasts about one year on the shelf. If you have matcha that has ‘expired’ I would recommend baking with it or making a delicious smoothie with it. Matcha doesn’t really go bad but it will oxidize over time.
Once matcha is opened, it really should be used up within three or four weeks — or, if you really want to push it, no longer than eight weeks to ensure optimum freshness, colour, and taste. Matcha is not your grandmother’s tea. You shouldn’t “save it for a special occasion.” There’s no better time than the present. It’s one of the reasons why I love to drink it. Every time feels like a special occasion and life is meant to be celebrated.
I have read many ways in which matcha should or should not be stored. If I plan on not opening it for a while, I will keep it in the fridge. Before I open the tin or bag, I always bring it to room temperature. You may want to write down the date when you open the tea on the tin or bag to ensure that you drink it within the month. This is never a problem in my house, we go through a lot of matcha. Once opened, seal and store at room temperature away from strong odours, heat or light. All you really have to worry about are the matcha Gremlins, the people in your household who use the last little bit of matcha up and forget to replace it. They are real!