Water temperature makes or breaks a cup of tea.
Steep green tea at 70 to 80 degrees Celsius for two minutes. Boiling water scorches the leaves and turns the cup bitter.
Black tea wants a full boil, 100 degrees, for three to five minutes depending on how strong you like it.
Oolong sits in between: 85 to 95 degrees, and it rebrews well — good oolong gives four or five infusions.