If you can only remember one thing about brewing tea, remember these two numbers: water temperature and steeping time. The same batch of tea, with different values for these two numbers, will yield two entirely different cups.
Temperature Guide by Tea Type
White Tea: 80–85°C. Water that is too hot burns the fine hairs and destroys the sweetness.
Green Tea: 75–85°C. This type is the most temperature-sensitive.
Oolong: 90–95°C. High heat is needed for the tightly rolled leaves to unfurl.
Black Tea: 88–92°C.
Pu-erh (Raw & Ripe): 95–100°C. Use truly boiling water.
Estimation Without a Thermometer
Boil and then remove the lid: after 1 minute, the temperature will be around 90°C; after 2 minutes, around 85°C; after 3 minutes, around 80°C.
Pouring boiling water through a gongdao bei (pitcher) before transferring it to the teapot will also reduce the temperature by about 5°C with each transfer.
Steeping Time
Gongfu style brewing (5g tea for a 150ml teapot): first steep 10–15 seconds; subsequent steeps add 5–10 seconds.
Large pot brewing (3g for 300ml): 2–3 minutes; pour completely into cups, do not let leaves steep in water.
Large-leaf teas need longer than broken-leaf teas. Broken-leaf teas release their compounds very quickly, making them prone to bitterness.
Fixing a Bitter Cup of Tea
Reduce the amount of tea first; don't rush to shorten the steeping time too much — less tea still retains its aroma, while under-steeped tea is bland and empty.
Lower the water temperature by 5°C.
Rinse the tea once quickly (3 seconds) before the first steep, especially for compressed Pu-erh cakes.