Chapter V · The Brewing · Section 3: A modern tea-science reading — reading “已上水老不可食也”

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Thesis

Read through modern tea science, “已上水老不可食也” is not a lab result but a set of variables: cultivar, soil, light and plucking standard.

Text

“Beyond this, the water is old and cannot be drunk.”

Context

超过三沸水就"老"了，不宜饮用——这是古人对火候的精准把握。

Evidence

• Collation: 本句紧承三沸，各本一致，无版本差异。
• Existing readings: 吴觉农指出"水老"即水中溶氧散尽、钙镁离子浓缩，茶味发涩——现代科学印证了陆羽"水老不可食"的判断。

Analysis

Modern tea science would split “已上水老不可食也” into cultivar, soil, light and plucking variables. 吴觉农指出"水老"即水中溶氧散尽、钙镁离子浓缩，茶味发涩——现代科学印证了陆羽"水老不可食"的判断。 They remain testable, but only with their conditions attached.

Conclusion

The section does not give a universal rule. It demonstrates a method: read the text, the annotation and the Tang context together before making a modern claim.

Source: The Classic of Tea, Chapter V · The Brewing, section 3; the original is in the public domain.

Water and fire magnify the difference. The same leaf at a higher temperature or a longer steep changes the sweet-bitter balance; the text only becomes operational at the brewing stage.

In Tang context, 吴觉农指出"水老"即水中溶氧散尽、钙镁离子浓缩，茶味发涩——现代科学印证了陆羽"水老不可食"的判断。. Tea was tribute, medicine and monastery drink at once, not a standalone commodity; the conclusion cannot be transferred without that context.

Storage adds another variable: moisture and temperature. 本句紧承三沸，各本一致，无版本差异。 Old and young tea do not share one shelf life, so “the older the better” is not a rule.