Chapter IV · The Vessels · Section 8: In Tang context — reading “第一煮水沸而弃其沫之上有水膜如黑云母饮之则其”

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Thesis

“第一煮水沸而弃其沫之上有水膜如黑云母饮之则其” only becomes legible inside Tang tribute tea, monastery tea and literati life.

Text

“When the water first boils, skim off the film that rises on the surface, like black mica; drinking it spoils the flavor.”

Context

水膜：头沸水面的浮膜。黑云母：黑色云母片。味不正：味道不正。

Evidence

• Collation: 各本一致。吴觉农注：此"水膜"为水垢与杂质浮沫，撇之使茶汤洁净。
• Existing readings: 吴觉农指出"弃其水膜"是唐代"洁水"的关键一步：水沸后矿物质与杂质浮于表层，撇去则味正——现代煮水同样讲究"刮沫"，此传统千年未变。

Analysis

The largest gap between Tang and now is that tea was simultaneously medicine, tribute and everyday practice. 吴觉农指出"弃其水膜"是唐代"洁水"的关键一步：水沸后矿物质与杂质浮于表层，撇去则味正——现代煮水同样讲究"刮沫"，此传统千年未变。 Without that, the chapter collapses into botany.

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 IV · The Vessels, section 8; the original is in the public domain.

A maker reads “第一煮水沸而弃其沫之上有水膜如黑云母饮之则其” through weather and soil first. 水膜：头沸水面的浮膜。黑云母：黑色云母片。味不正：味道不正。 That is not far from how we judge a mountain and a picking window today.

The vessel is not background. 水膜：头沸水面的浮膜。黑云母：黑色云母片。味不正：味道不正。 The same leaf in a different bowl, grinder or sieve changes aroma and texture; vessel and tea are defined together.

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.