Water is very important for brewing tea as it makes up 90% of the end tea. Together with the quality of tea, correct measurement, proper steeping time , proper water temperature and teapot, the quality of water is one of the most key elements for brewing good oolong tea. Therefore, try to begin with good water when making oolong tea.
Spring water is the best water for making oolong tea. Try not to use distilled water as water purified of its mineral content produces a flat tasting infusion. Fresh water that contains more oxygen will enhance the taste of the tea. Here we have a list of the best water in China and it is believed that those on the list are good choices for brewing oolong tea.
Hot tap water or water that has already boiled for a long time are not recommended as such kind of water result in a flat and dull tasting tea with little aroma. The water should be brewed around 90°C to 100°C (194°F to 212°F).
Related: Oolong Tea Preparation