There are two kinds of puer tea: shu (ripe, cooked, heavily fermented) and sheng (raw, slightly fermented).
The main difference between the two types is that shu puers undergo an extensive (several months to a year) fermentation process, whereas sheng puers are fermented slightly, for a much shorter period of time.
Puer tea @ Kunming tea market: neatly pressed cakes, loose sheng, and lumpy chatou of shupu
Puer production process
Shu and sheng puers are both derived from maocha (毛茶), which essentially, refers to sun-dried tea leaves. The dried leaves can be stored as raw material or used immediately for production. To make sheng puer, maocha is steamed and pressed into cakes, bricks, nests, and other shapes. Some people sell it in loose form too. Maocha can also be soaked in water for about a week in order to kickstart the natural fermentation. Sheng puer buds and leaves keep their distinctive greenish color. This tea is ready for immediate consumption or aging.
The process of making shu puer is quite different. Large tea leaves and buds are heaped together in a large room or container. Once a certain amount of water is added to the pile, the room temperature is increased and changed accordingly to adjust the fermentation process. The thermophile (i.e. heat-loving) microorganisms then begin to work their magic on tea by changing its color, texture, and chemical composition.
Grades of puer
Once the fermentation process is over, tea is sent through special sieves that separate the freshly fermented mass into tea of various categories: gongting, extra, 1st, 3rd, 5th, and 7th grades. Traditionally, there are no 2nd, 4th, and 6th grades to make differentiation easier. What determines the class of tea? In the case of shu puer it is primarily the size and shape of tea buds and leaves. Gongting, for instance, is supposed to be buds only with each bud averaging 1-1.5 cm (half an inch) in length. Extra class is 50-60% buds and 40-50% leaves. First grade puer is approximately 30% buds and 70% leaves. Third grade has leaves that are larger in size and the bud content is accidental. Fifth and seventh grades are entirely made up of leaves, the main difference being in size, thickness, and texture of tea material used.
When I heard about the puer making process, my first question was why different grades of puer are not fermented separately. First of all, that would make the price of tea much higher, since leaves would have to be separated manually prior to fermentation, which is possible physically, but unviable economically. The second reason is that buds fermented separately from large leaves may not obtain the desired taste and aromatic qualities. In other words, the chemistry involved in the fermentation process requires the enzymes contained in both buds and leaves to produce good quality tea.
Why press puer tea
Both sheng and shu types of puer can be sold in loose form, but it has become common practice to press puer into cakes and nuggets of various shapes and sizes. Cakes are much easier to store and transport than crates or bags of dry leaves. Pressed teas also keep their taste and fragrance for much longer periods of time. However, during the pressing process, a lot of leaves get damaged. This is particularly true for smaller nuggets that have a relatively high proportion of fragmented and virtually no undamaged leaves. However, these changes are purely cosmetic in nature, i.e. having zero effect on the taste and quality of pressed puer.
Chinese law requires tea manufacturers to mark their cakes with the year in which the tea was pressed, rather than when it was processed. The tea inside a cake that was pressed, say, two years ago could actually be older than that. Tea traders may or may not want to share this information with you, but they usually do if you ask specifically. Whether or not their answer reflects the reality is a mixture of luck and guanxi (Chinese word for rapport).
To age or not to age
In fact, one of the most common questions asked about puers is how old they are. There is a common belief that the older puer is, the better its taste, aroma, and health benefits. To make the long story short, this assumption is generally true, but only if the tea is stored properly.
Sometimes puer is made with the focus on quality and not the taste. For instance, a tea manufacturer may wish to create an unblended, spring-harvest, buds-only cake of gongting shu puer. Sounds amazing, right? Not necessarily. If consumed within a year or two after production, this tea may not have some of the taste, aroma, and brewability qualities that a tea connoisseur might expect to observe. However, let it age properly for a few years, and you are very likely to get a cake of excellent-tasting puer that can be brewed up to ten times.
Conversely, the very same tea manufacturer may decide to create a blended, half leaves and half buds, moderately rough-looking cake of shupu (shu puer). Some people might say that the manufacturer is trying to save money. Others would complement his desire to make tea that tastes reasonably well the year it is pressed. Who is in the right here is a rhetorical question, so I’m going to leave it unanswered.
Some personal thoughts
Let’s not forget that tea is made for drinking, not for storage or aging. I like to think about it this way: would I buy a car that I need to work on at home for a while before I can drive it safely and comfortably? Probably not, unless it’s a bargain or something. The same rationale applies to tea. Why buy tea that I don’t like the moment I am sampling it at the shop or market? I just buy the tea that I like and feel happy that it has an insanely long shelf life.
While it is certainly true that properly aged puer tea is likely to reveal some hidden properties, it is important to remember that a great deal of the tea-aging paradigm is the result of the puer investment bubble that captivated China about a decade ago. That bubble burst in 2007, leaving scores of thousands of Yunnan farmers and tea brokers poor, but its ripple effects in form of multiple myths and legends regarding scientifically confirmed and imaginary properties of puer are still affecting the way people think about this tea in the whole world.
In fact, tea aficionados like myself are partly responsible for perpetuation of such myths. Whenever I go to a shop that sells puer tea, I often ask about the age of cakes that take my fancy. I know that it’s silly, but I simply can’t help it. It’s a great conversation starter, especially when dealing with people who speak a dialect of Chinese that I’m not familiar with. I’m fully aware that by asking this question, I reveal the level at which my choices can be manipulated. Fortunately, I’ve been exposed to tea culture long enough to rely on my palate, and not eyes or ears.