"It is smart, its taste is light and clean, its use is annoying, and its work is harmonious." Which tea book is it from?

On daguan tea. According to relevant records, the phrase "its essence is clear, its taste is light and clean, its use is boring, and its work is harmonious" comes from the book "Daguan Tea Theory" written by Chen in Ming Dynasty. This book on tea science is the most famous monograph on tea in the history of China. There are 30 volumes in the book, which introduces the knowledge of tea varieties, classification, production, preservation, tasting and brewing in detail. Among them, the phrase "its essence is clear, its taste is light and clean, its use is boring, and its function is harmonious" was mentioned by Chen when discussing the nature and efficacy of tea. This sentence means that tea tastes cool and elegant, can clear away heat and relieve summer heat, relieve boredom and refresh oneself, and has the function of harmonizing human body functions. This is one of the reasons why tea is considered as a healthy drink in China culture.