Chinese Green Tea

Lu Yu wrote The Classic of Tea in 760 AD, and the first thing he addressed after the tea itself was the water. Mountain spring water is best, he wrote: slow-flowing, filtered through stone, cold and clean. River water is acceptable. Well water is last resort. Twelve centuries later, the principle has not changed. Chinese green teas (Longjing, Biluochun, Huangshan Maofeng, Taiping Houkui) are pan-fired rather than steamed, which gives them a roasted, sometimes nutty character that is more robust than Japanese green tea. But they still demand soft water. The ideal, in both traditional and modern Chinese tea culture, is water with a hardness between 17–68 ppm. This profile sits in that range: calcium at 12 ppm and magnesium at 3 ppm give a total hardness of around 42 mg/L as calcium carbonate. Soft enough to preserve colour and clarity, mineralised enough to have body.

The slightly higher bicarbonate (30 ppm, compared to 25 for Japanese green tea) reflects the fact that Chinese green teas can tolerate a touch more alkalinity. The pan-firing process develops more robust flavour compounds that are not as easily flattened by mineral content. Chinese tea culture also emphasises what it calls huo (liveliness) in water: a quality associated with freshly drawn spring water that has been aerated by flowing over rocks. In practical terms, this means well-oxygenated water with minimal staleness or chlorine. The mineral profile is secondary to freshness, but it sets the baseline.

Too much calcium and the Longjing loses its chestnut sweetness. Too little mineral content and the liquor tastes empty. The traditional mountain spring water that Lu Yu praised was not distilled; it was naturally soft, lightly mineralised, and alive.