From the experts: This is a general guideline for tea steeping temperatures and times. Some teas will differ. For example, we recommend steeping Darjeeling tea at 195 degrees for three minutes as we find it can scald the leaves, causing bitterness. Green teas vary greatly but in general the below steeping times and temperatures give a you a good baseline.
—The London Tea Room
Black tea at 205° – 212°F (rolling boil)
Steep: 4 minutes
Green tea (China) at 160° – 170°F
Steep: 2 minutes
Green tea (Japan) at 140° – 150°F
Steep: 1 minutes
Oolong tea at 185° – 195°F
Steep: 3 minutes
White tea at 195° °F
Steep: 4 minutes