Nuances of Tea Classification

by Tony Gebely 6,751 views10

nuances of tea classification featured image

A tea processing chart refers to a chart that shows the processing steps that different tea types go through after being plucked and before they reach your cup. Tea processing charts have been essential items in the toolbelt of tea educators for years. However, nearly every processing chart that exists today excludes many styles of tea and sometimes entire types of tea. I posted the first version of my tea processing chart here on World of Tea in 2013. Since then, I have made countless edits to it in an effort to create an easily understandable tool for tea education. Early on, I adopted a lumper mentality.

In any discipline that requires placing things into categories, there are generalists and specialists. These two factions are often referred to as lumpers and splitters. In general, lumpers prioritize similarities over differences and splitters prioritize differences over similarities. Tea snobs are inherently splitters; always pointing out differences in things in order to make themselves feel smarter than the average person. Splitters love to say things like “it’s more complicated than this!” or “there are no absolutes in tea!” And while they may be right, I don’t believe that the splitter mindset has any place in beginner’s tea education.

A major turning point in my tea study was when I stopped trying to create a chart outlining all of the steps that each tea type goes through and began to evolve the chart so that it only exhibited the minimum steps required to be considered a tea of a specific type. This simple change in thinking led to the processing chart in it’s current form.

tea processing chart

What follows is an exploration of the challenges that exist when classifying the diverse world of tea and ultimately, what led to the current thinking exhibited in the latest processing chart. But first, some groundwork… we will be working with seven main categories of tea, each defined by the unique processing steps they go through: green tea, yellow tea, white tea, oolong tea, black tea, fermented tea and altered tea. It may help to read my post A New Look at Tea Classification so that you better understand the terms used in this post before continuing. And finally, this post is really nerdy, so I apologize in advance!

Green Tea

green tea processing chartIn one simple sentence, green tea is a type of tea made from leaves that have been withered, fixed and dried. There’s no controversy surrounding the fact that leaves destined to be green tea are heated (via a processing step called fixing) and thus are not allowed to oxidize. It is this prevention of oxidation defines green tea. However, the amount of withering that occurs before the leaves are fixed has led to a lot of confusion in the tea world.

There is a notion that tea leaves destined for green tea production are plucked and rushed to the processing facility to be fixed, while this is likely the case when steamed greens are being produced, it isn’t the case for most pan-fired green teas. Leaves that will be pan-fired go through a distinct withering step to prepare them for further processing. Regardless of the style of green tea being produced, the leaves are allowed to wither and are flaccid once they reach the pan or the steaming machine. Whether or not the producer considers withering a processing step or intentionally withers the tea leaves before fixing them is another matter altogether and the heart of the confusion surrounding withering in green tea production.

Yellow Tea

yellow tea processing chartYellow tea is defined by a processing step known in Chinese as Men Huang. Translated, this means sealed yellowing. During men huang, small portions of fixed tea leaves are wrapped into bundles either using paper or cloth. While wrapped, the leaves slowly change color from green to yellow-green as chlorophylls are broken down, the vegetal flavors within the leaves begin to mellow and the leaves partially oxidize.

The trouble with yellow tea production today, is that some yellow tea producers are skipping this defining men huang processing step altogether, essentially selling a green tea as a yellow tea. This practice is common among Huoshan Huangya producers in China’s Anhui province.

Another fun yellow tea classification issue arises with a tea from South Korea called “Hwang Cha” which translates directly to Yellow Tea. Turns out that this tea is nothing like yellow tea at all in the Chinese sense. South Korean Hwang Cha is produced by withering tea leaves, they then go through a men huang process and are then dried. Because of the lack of a fixing step here, oxidation is able to run it’s course during men huang and the resulting tea is more of a highly oxidized oolong or black tea in nature. In South Korea, it is classified as a balhyocha (발효차), which translates to “fermented tea” but really refers to “oxidized tea.”

white tea processing chartWhite Tea

Many consider white tea to be unoxidized due to the fact that raw material destined to be white tea doesn’t go through a processing step labeled oxidation. However, it is during a long withering period, sometimes lasting several days that the leaves slowly oxidize. The oxidation that occurs in white tea production is minimal, but it can not go unmentioned. Another thing that many tea companies get wrong when defining white tea is the fact that white tea is not always made up of buds. Bai Mu Dan, and it’s lower grade variants, Gong Mei and Shou Mei are made up of buds and leaves. White tea production is not only limited to China’s Fujian province either, it is now being produced in small quantities in Sri Lanka, India, and Nepal. For a laugh, look at the definition of white tea taught by the Tea Council of the USA, it’s quite embarrassing.

Wulong Tea

Wulong refers to semi-oxidized tea. But semi-oxidized is a term that needs some unpacking. Regardless of the style of wulong being produced, processing begins with withering. From here we experience some variance where the initiation and control of oxidation is concerned. Traditional half-ball shape oolongs like those from China’s Fujian Province and Taiwan are either shaken or tumbled, a process known as Yao Qing (摇青) literally, rocking the green. The goal here is to gently bruise the edges of the leaves, initiating oxidation. Some teas coming out of India and Nepal labeled oolong do not go through this process, rather, they are rolled using an orthodox rolling table. The wulong nature of these teas comes from the prevention of oxidation, much of the process resembles black tea production, but the leaves are dried before reaching a normal black tea level of oxidation resulting in a semi-oxidized tea. Some tea experts hold that these styles of tea do not deserve the wulong designation.
oolong tea processing chart
Rolling is another important step in producing half-ball style wulongs as in Anxi and Taiwan. Here, the leaves go through an iterative process called cloth-wrapped kneading where bundles of leaves are wrapped in cloth then kneaded. The wrapped ball of leaves is then broken apart, then re-wrapped and the process begins again. This is an iterative process that is performed many times.

First Flush Darjeeling teas are also a source of confusion as they are typically only lightly oxidized to exemplify the first harvest of year. Because of their semi-oxidized nature, many tea experts consider them to be wulong, though they are often marketed as black teas. Some even refer to First Flush Darjeeling tea as lightly oxidized black tea which of course is an oxymoron because the defining characteristic of black teas is that the leaves are fully-oxidized during production.

Thus, in order to handle all semi-oxidized teas in a processing chart, I refer to the initiation of oxidation as “rolled/bruised” and I’ve omitted the cloth-wrapped kneading step because while that is a defining characteristic of several teas on the style level, it is not a defining characteristic of the wulong type itself.

Black Tea

black-tea-processingBlack teas are often described as fully oxidized teas. To be more accurate, let’s say mostly oxidized as it’s chemically impossible to fully oxidize tea leaves without first grinding them into a fine powder. The basic process for making black tea from fresh tea leaves is: withering, rolling, oxidation, and drying. The goal of black tea production is to induce and control oxidation until the tea leaves achieve a prescribed level of oxidation.

There isn’t much confusion with this type of tea, black tea production is quite straightforward as it is the most produced tea type in the world. It is important however, to note that what most of the world outside of East Asia refers to as black tea is known to the Chinese (and most Asian countries) as red tea (红茶, hong cha). Calling this tea type black tea is confusing because the Chinese already have a tea category called Hei Cha (黑茶) which translates to black/dark tea. Calling this tea type red tea is also confusing because most of the western world uses the term red tea for African Rooibos, which isn’t tea at all but rather a tisane from leaves from the Aspalathus linearis bush. That’s fun, right?

Some confusion may arise when teas that are not close to being fully oxidized are marketed as black teas. In fact, I was sold a lightly-oxidized black tea while traveling in China in 2015. There are two schools of thought here when encountering these semi-oxidized “black teas,” the first is that if the tea was produced without any sort of Ya Qing (see Wulong above) process, then it cannot possibly be considered a wulong, and the tea is oxidized much more than a traditional wulong, so it must be a black tea! The second school of thought would say that the producer’s intention was to create a black tea and the production techniques resemble black tea production, so it must be a black tea! There truly is not a wrong or right answer here.

Fermented Tea

fermented-tea-processingFermentation in tea production refers to the breakdown of substances by bacteria, yeasts or other microorganisms. Fermented tea, a source of so much confusion in the West. I call this category fermented tea because it includes heicha, puer, and several fermented Japanese teas. If I were only referring to fermented teas from China, I would call this category, heicha. Yes, heicha. Puer is not the “6th tea category” yet I see tea books and classification charts with no mention of heicha whatsoever. Puer-heads typically shake their fist at me when I say this, but take a look at the processing steps that I list for the production of fermented tea: withered, fixed, rolled, fermented. You may notice the omission of several processing steps sometimes associated with these styles of tea, drying, compression, etc. I dramatically simplified the processing chart so that all fermented teas fit into it. Drying had to go because the drying step occurs before fermentation for Shu Puer production and after fermentation for most Heicha production. What’s left are processing steps that define fermented tea, all of it.  

Let’s talk about Puer, specifically Sheng puer, this tea is more like a green tea in production, but the intent (at least today) is to age this tea which refers to a combination of slow oxidation and fermentation over time. In my unscientific opinion, the aging of sheng puer is more oxidation than fermentation, but fermentation does occur and therefore this is considered a fermented tea. The method of fermentation differs from style to style, Shu Puer and Heicha both go through a wo dui / piling step (and some consider Shu Puer to be part of the Heicha category). Sheng’s fermentation happens during the aforementioned aging.

Altered Teas

Any tea type above can be altered. Altered teas refer to teas that go through additional processing steps during or after primary processing before being sold. This can refer to flavoring, scenting, blending, smoking, aging, decaffeinating and grinding. The majority of teas sold in the United States are altered in some way.

As always, I welcome any and all criticism on this post. It is the feedback I receive here on World of Tea that allows my content to evolve.

Comments (10)

  1. Edit to my comment: sorry, I see now that in the full description of the fermented category in this article, you describe why you left out “dried” (not because it doesn’t occur, but because it occurs at different times for different styles and thus is not a defining part of the process for fermented teas. Would still be interested to hear about the difference for black teas.

    1. Hi Michael, Thanks for the comments. For black tea, “dried” and “fixed” can be used interchangeably. I’m actually going to switch it to “dried” in the book’s second edition.

  2. I’ve found your tea classification very helpful. I do have a few questions. In the book, the last step for black tea is “fixed” while in this article it’s “dried”. Fermented teas omit “dried” both in the book and here. Obviously all teas are dry at time of purchase, so can you clarify why the step is listed for some types and not others? Is it because the “fixing” and “fermenting” steps also dry the tea and so drying does not need to be listed as an additional step?

  3. I love learning about tea while I’m getting an education on strategies for teaching about tea! Right on target with your philosophy regarding the needs of the beginners mind and lumping!
    Great work, Tony!
    Lou Berkley
    San Francisco

  4. I can’t really bring on criticism of this artice as I’m a total newbie as far as tea goes.
    However, I can say that this article was incredibly helpful and offered information I badly needed.
    I highly appreciate the effort that went into making this!

  5. “In my unscientific opinion, the aging of sheng puer is more oxidation than fermentation,” there is a recent paper in PLoS ONE (that I’ve been meaning to blog about) on the puer microbiome and one of the cool findings is that the oldest sheng in their study (28 years) has a microbiome most similar to the shu pu in their study. It’s a sample size of 1, but still an indication that fermentation could be important for sheng puer.

  6. Very interesting, informative and educative

  7. This is a great educational piece that offers tea drinkers and vendors alike the badly needed clarifications on the subtleties in tea types and processing. Mislabeling is plaguing the tea industry. This article deserves wider media attention and social sharing.

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