Water that is too hot will destroy polyphenols and other health-promoting compounds in tea (as well as affect its flavor quality). We recommend following the brewing instructions listed on each box (ideal water temperatures are 170F for green, white and oolong teas, and 180F for black tea).
Cold water will not affect the polyphenol content or the other healthful compounds found in our teas. If you'd like to enjoy our black tea as an iced tea, we recommend first dissolving it in a little bit of hot water (1oz will do), and then adding cold water and ice. That being said, studies have shown that cold beverages are not as beneficial for gut health as warm ones.