Once you store brewed tea in the refrigerator, you are essentially creating iced tea. The tea, whether black or green, should last for about two days in the fridge before it goes stale or flat. The Centers for Disease Control and Prevention recommends storing tea at room temperature for a maximum of eight hours. Take care to store it so that it doesn't absorb flavors from other nearby items in the refrigerator.
Allow the brewed tea to cool to room temperature. Place it in the refrigerator in a glass, rather than a plastic, pitcher to keep its flavor neutral. For even better results, store the tea in Mason jars with the lids on, to prevent the tea from acquiring an odor. Because exposure to oxygen makes the tea go flat, small jars with minimal exposed surface area work best to keep brewed tea fresh.
You can also freeze brewed tea to make ice cubes that allow you to speed up your smoothie making and add a welcome ice slush to your blender. Pour the tea into ice cube trays and allow them to cool on the counter. Place the trays in the freezer for 12 hours or more, until firmly frozen. Pop out the tea cubes, and put them back in the freezer in a plastic zipper-top bag. These stay usable indefinitely.
The CDC says the risk of bacterial contamination from stored tea is more theoretical than actual. Even so, if you want to be extra-safe: