The traditional method of making or brewing a cup of tea is to place loose tea leaves, either directly or in a tea infuser, into a tea pot or teacup and pour freshly boiled water over the leaves. After a few minutes, the leaves are usually removed again, either by removing the infuser, or by straining the tea while serving.
Most green teas should be allowed to steep for about two or three minutes, although some types of tea require as much as ten minutes, and others as little as 30 seconds. The strength of the tea should be varied by changing the amount of tea leaves used, not by changing the steeping time. The amount of tea to be used per amount of water differs from tea to tea, but one basic recipe may be one slightly heaped teaspoon of tea (about 5 ml) for each teacup of water (200–240 ml) (7–8 oz) prepared as above. Stronger teas, such as Assam, to be drunk with milk, are often prepared with more leaves, and more delicate high-grown teas such as a Darjeeling are prepared with somewhat fewer (as the stronger mid-flavours can overwhelm the champagne notes).
The best temperature for brewing tea depends on its type. Teas that have little or no oxidation period, such as a green or white tea, are best brewed at lower temperatures, between 65 and 85 °C (149 and 185 °F), while teas with longer oxidation periods should be brewed at higher temperatures around 100 °C (212 °F). The higher temperatures are required to extract the large, complex, flavourful phenolic molecules found in fermented tea. In addition, boiling reduces the dissolved oxygen content of water. Dissolved oxygen would otherwise react with phenolic molecules to turn them brown and reduce their potency as antioxidants. To preserve the antioxidant potency, especially for green and white teas brewed at a lower temperature, water should be boiled vigorously to boil off any dissolved oxygen and then allowed to cool to the appropriate temperature before adding to the tea. An additional health benefit of boiling water before brewing tea is the sterilisation of the water and reduction of any dissolved VOCs, chemicals which are often harmful.