Brewing a perfect cup of tea requires attention to detail. While the quality of the tea leaves is crucial, factors such as water quality, teaware, brewing method, timing, and water temperature also play significant roles.

Ancient Chinese tea literature, like Cai Xiang's "Tea Record" from the Song Dynasty and Xu Cishu's "Tea Commentary" from the Ming Dynasty, discusses the impact of different water temperatures on tea. Terms like "undercooked water," "overcooked water," and "just-right water" may differ in name but share the same principle.

"Undercooked water" refers to water that hasn't reached boiling point, around 60-65°C. At this temperature, even delicate green tea leaves won't fully release their flavors, resulting in a weak and bland brew with leaves floating on the surface.

"Overcooked water" refers to fully boiled or over-boiled water, around 100°C. This high temperature can "scald" delicate green tea leaves, causing excessive release of tannins and caffeine, leading to a bitter and astringent taste, and turning the tea liquor yellow.

The ideal temperature for brewing green tea is "just-right water," described as when bubbles form but before full boiling, around 80-95°C. For tender teas like early spring harvests, water boiled to 90°C and slightly cooled to around 80°C is optimal. This preserves the tea's amino acids, vitamin C, and delicate aromas while minimizing bitterness.