The 19 Areas of Yixing & The 3 Types of Yixing Clay

NOTE: this post is out of date. Those Interested in Yixing Teapots are suggested to read An Introduction to the Art & Science of Chinese Tea Ceremony: Yixing Teapots – Knowledge, Connoisseurship, and Technique

It has been known as late as the Ming Dynasty that tea was most suitably brewed in a Yixing teapot. The special Yixing clay helps to refine and round out flavor profile of fine Chinese tea, and can help you achieve the ultimate goal of GongFu – brewing good tea.

I'm smiling becuase you have no idea what comes next

Yet finding, sourcing, and understanding Yixing can quickly become an expensive and sisyphean undertaking. The vast majority of “Yixing” wares available on the market are frauds, made out of industrial clay using slurry molds. Learning to identify real Yixing requires experience with known samples of known provenance and known age – that’s particularly difficult given that Qing and ROC yixing artists were faking Ming Dynasty pots with real high quality clay for generations. Determining the age or provenance of a teapot is difficult or impossible even for experts.

Should you find a Yixing you trust as real, the task continues to grow exponentially in complexity; not all Yixing pots are created equal, and there is in fact a wide range of sub-types of Yixing clay commonly used to make Yixing teapots – some of which should only be used for specific teas or under specific conditions.

At the Tea Institute (of which I am only an advisor) we have set out to analyze the chemical composition of the clay, the clay’s effect on the sensory attributes on various classes of teas, and the chemistry that causes these sensory changes. Eventually, this research will yield a better scientific understanding of the magic and allure of Yixing clay.

I accidentally slipped into my investor pitch for a moment - sorry!

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I’m Back

Baller Status Unlocked

Namaste friends, romans, 茶人, & countrymen! It has been far too long, with far too little tea and tea related adventures since I last posted.

But the wait is over.

After this most successful event, the 2015 Yixing Teapot Exhibition, hosted by the Tea Institute at Penn State, I feel alive to the allure of tea once again.

Ryan Ahn (狮子) has done an unbelievable job of taking over the institute I founded and I am so happy to remain involved in an advisory role. Ryan and his executive team are 100x better at recruiting than I (and my executive team, sorry guys) ever was/were.

one of us one of us one of us

Under Ryan and the new executive board, the Institute has grown to 44 active members! (all of whom are directly descendent from my tea linage, making me far more proud than the parents of an honor roll student)

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Thoughts on Classifying Teas

This will be a quick post lacking the photos and reference links in most of my diatribes…

The Tea Institute works on a semester lecture cycle, where our new students (prospective researchers) join one of our 3 tea ceremony clubs (Chinese, Japanese, or Korean), learn a ceremony up to a point of proficiency, and can then test into the Institute (the ‘Tea Specialist Examination’).

I run the lecture / lesson cycle for Chinese Tea Ceremony, and for the last 6 semesters have been refining my lectures from ~2ish hour rambles (painful) to 45min soliloquies (almost beautiful).

For the last few weeks I have been lecturing on Tea Production Methodologies and classification; these are topics that merit their own 8 week lecture cycle, but we distill them into 1 lecture per class which for the most part works quite well. As a derivative of the standard Chinese classification system we use percentage oxidation to determine primary classification of tea – these are the ranges listed below:

  1. Green (0 – 6%)
  2. White and Yellow (0 – 10%)
  3. Mainland Oolongs (25 – 70%)
  4. Taiwanese Oolongs (15 – 90%)
  5. Sheng Pu’er (0 – 20%)
  6. Shou Pu’er (~0 – 25%) & other Post Fermentation Teas
  7. Chinese Red Tea (~100%) & non-traditional teas

Yet, these distinctions are not without their problems; all classification is at some level arbitrary! (and it’s impossible to determine actual level of oxidation of any specific tea without Gas or Liquid Chromatography – so don’t believe anyone who gives you a specific oxidation percentage!)

These ranges aren’t perfect, and its probable that you wouldn’t think too highly of a tea at the minimum or maximum oxidation of its class; but they are good generalizations. There are exceptions to every rule, but you should still know the rule.

White, Yellow, and Green tea all have overlapping ranges for percentage oxidation; a first pass at this level of analysis would have you believe these teas should be categorized together. That could work – many in China do classify White and Green tea together.

At the Institute, we don’t. We use a 2 stage process of classification: Percentage Oxidation, and Processing Methodology. Thus, White Tea goes through a withering before ShaQing (deactivation of the oxidizing enzyme), while Yellow tea goes through a process creatively known as Yellowing (withering in the presence of excess moisture).

Sheng Pu’er and Shou Pu’er follow the same example: same range of oxidation, yet a difference in processing leading to distinct classification. This is all well and good as I would hate to ache for a Sheng flavor profile only to brew a Shou.

This is an intuitive and working system.

Where this system of classification fails is in the cup. We don’t classify teas by flavor profile, yet the point of tea is appreciation through consumption (sweeping over generalization, but don’t care this post).This means that classification is disjoint from our reason for classification; selecting teas with the flavor profile we desire.

Thus, when oxidation and processing are no longer the most important factor in determining flavor profile, which is quite rare, we are left with a cup that resides “out of character”.

We have a policy in the tea house to force our members (including myself) to Identify a tea by taste alone before we will tell them what it is. I started thinking about this classification problem when I misidentified a thermos brewed YueGongBai, a white tea, as a DianHong, a Yunnan red tea. [Thermos brewing is another great habit; you can learn a lot about a tea by ‘stress testing’ it (holding a tea at a very high temperature until it reaches maximum solubility of the water)].

The new, and dedicated student was quick to jump on my mistake; he thought it was quite heinous to mistaste a white for a red, and in other circumstances he would be right! This is not a mistake I would have made from a Gaiwan brew.

What might pardon me from sin? YueGongBai is made with Yunnan DaYe cultivar, the same cultivar used to make (most) Pu’er and DianHongs. When brewed in a thermos, the flavor attributes generated by the DaYe cultivar far outweighs the flavor attributes modulated by processing. That is to say, I identified the cultivar!

Did I miss identify the tea? Yes. But, I must question, was this a personal fault, or a fault of classification? – comment below.


On another note:
The Institute has been overrun with all of our new projects and research this semester, and I have personally been running a work marathon juggling my start up, the Institute, research, okapi hunting, and classes (not to mention competition fencing and climbing). And sleeping. Need sleep….

I promise more posts with more of a research focus soon.
[unless all you want chaxi photos, but you’d need to tell me that in the comments]

– Jason

Tea History Lecture Notes (Tang to Ming)


  • ShenNong
  • Yunnan Minority groups
  • Uses


Tang Dynasty (618 – 907)

  • During the Tang Dynasty, tea drinking customs spread quickly in the north of China on the basis of development in south China.
  • The flourishing and influences of Buddhism were important factors in promoting tea drinking customs to spread from the South to the North of China.
  • Practitioners of Chan or sat in meditation were required neither to sleep nor to eat food at night, but all of them could drink tea.
  • Another important factor for the flourishing of tea affairs was the appearance of tribute teas for imperial court use. Tea drinking was popular in the imperial court of the Tang period and there were many forms of tea ceremonies and tea parties.
  • The imperial court attached great importance to tea production. In 770CE, Emperor Tang Daizong had Guanpei (Governmental baking) established on Guzhushan Mountain in Changxing of Zhejiang (a special production base for plucking and processing tea for imperial court use) .
  • Every tea growing province had a tribute tea
  • Processing: The plucked tea leaf was steamed in a steamer, ground in a
    • mortar, compressed into cake, dried and strung with rind of reed or
    • bamboo. The cake tea was ground into powder, shifted and cooked in a
    • caldron before drinking. It could be mixed with a verity of things.
  • The Tang poet Lu Tong (790-835) devoted most of his poetry to his love of tea.
  • The 8th century author Lu Yu (known as the Sage of Tea) even wrote a treatise on the art of drinking tea, called the Classic of Tea (Chájing).
  • Although wrapping paper had been used in China since the 2nd century BC, during the Tang Dynasty the Chinese were using wrapping paper as folded and sewn square bags to hold and preserve the flavor of tea leaves.
  • During this Time, Tea was a State Monopoly


Song Dynasty (960 – 1279 CE)

  • Tea plantation in the Song Dynasty was three times the size that it was during the Tang Dynasty.
    • According to a survey in 1162, tea plantations were spread across 66 prefectures in 244 counties. The BeiYuan Plantation (North Park Plantation) was an imperial tea plantation in Fujian prefecture. It produced more than forty varieties of tribute tea for the imperial court.
  • Only the very tip of tender tea leaves were picked, processed and pressed into tea cakes, embossed with dragon pattern, known as “dragon tea cakes”.
  • The state monopoly on Sichuan tea was the prime source of revenue for the state’s purchase of horses in Qinghai for the Song army’s cavalry forces.
  • CháZào — Zhu Xi
    xianweng yíshízào
    wanzài shuizhongyang
    yinbà fangzhouqù
    cháyan niaoxìxiang
  • ‘Tea Stove’ by Zhu Xi
    Stone stove left behind by immortals,
    Lies crooked in the center of the stream.
    Tea finished, two boats drift on abreast,
    Tea smoke; wafting delicate fragrance.
  • The practice of boiling the water separately and whisking tea came into being
  • The Rise of tea competitions
  • Over 32 implements for preparing tea
  • It was enjoyed by all social classes at the time. The competitors cooked the tea by some specific procedures and game rules. By comparing the taste, color, smell and quality of the tea soup, the winner will be respected as the most skilled, experienced and knowledgeable tea master who controlled the Tao of Tea. During the
  • Song Dynasty, many emperors were loyal fans of the tea competition.
  • Tea Spread to Japan


Yuan Dynasty / Mongols (1271 – 1368)

  • Eradicated the elaborate ceremony
  • Whole leaf tea came into vogue


Ming (1368 – 1644 CE)

  • Renowned for its exceptional porcelain
  • The introduction of the Gaiwan
  • The Tibetans, keen to maintain good relations with the Chinese emperors, traded horses for tea replacing the Mongol’s as their main trading partners for these essential animals.
  • Ships sailed in and out at just about every Chinese harbor with valuable tea filling the holds. Tea was sold to many Southeast Asian and some African countries on the Indian Ocean coast.
  • In 1610 tea arrived in Europe via Macau on a Dutch merchant ship.
  • Jingdezhen