"Even though I'm using the same tea leaves, it tastes different from what I had at the source or a specialty shop"—the reason for this often lies in the "water." Over 99% of tea is water. Japanese water is essentially "soft water" with low mineral content, providing a blessed environment that is exceptionally well-suited for drawing out the delicate aroma of tea leaves. Here, we explain the criteria for selecting water to make Chinese tea taste its absolute best using Japanese water.
1. Water Hardness and Tea Extraction Balance
- Soft Water (Hardness 20–60 mg/L): Common Japanese tap water and domestic mineral water. Because it is low in calcium and magnesium, the aroma and umami components of the tea leaves are extracted directly. It is ideal for green tea, white tea, and high-mountain oolong tea.
- Medium-Hard Water (Hardness 80–150 mg/L): The moderate minerals harmonize with heavy catechins and roasted aromas, adding depth to the flavor. It can be suitable for smoothing out the edges of Wuyi rock tea or aged fermented pu-erh tea.
- Very Hard Water (Hardness 200 mg/L or higher): If the hardness is too high, calcium binds with the tannins in the tea leaves, creating a film that prevents both the aroma and flavor from being extracted (unsuitable for Chinese tea).
2. The "Dechlorination Boiling Method" to Improve Tap Water
Japanese tap water is strictly regulated for quality and is very sanitary, but the chlorine used for sterilization (the smell of chlorine) can ruin the delicate aroma of Chinese tea.
- Use tap water that has passed through an activated carbon water purifier.
- Keep the kettle lid slightly ajar, or let it boil vigorously for 1–2 minutes even after it reaches a boil (to ensure complete vaporization of chlorine).
- Bring freshly drawn water, which is rich in air (dissolved oxygen), to a boil quickly over high heat.
3. Changes in Water Quality from Copper Kettles and Iron Teapots
When water is boiled in a copper kettle or iron teapot, the action of trace metal ions and uniform heat conduction makes the water feel smooth and velvety on the palate. This is why metal-crafted kettles continue to be beloved as a heat source for Chinese tea ceremonies.
