Pu'er tea or Bolay tea, is a rich full bodied tea with an earthy taste.  Much like wine, Pu'er is fermented thus older tea is often more valuable than more recent vintages.  Usually sold in cakes, the Chineses have a saying, "Rich men drink green tea, Gentlemen drink Pu'er." This type of tea made from a "large leaf" variety of the tea plant (Camellia sinensis) and named after Pu'er county in Yunnan, China.

Pu'er tea can either be purchased as either raw/green (sheng) or ripened/cooked (shuo). Sheng and shou pu'er are roughly classified on an oxidation scale as either a green tea or fermented tea. The fact that pu'er fits in more than one tea type creates some problems for classification. Due to this, pu'er is almost always sold as a post-fermented product. Unlike other teas that are ideally consumed shortly after production, pu'er can be drunk immediately or aged for many years. As a result, much like wine, pu'er teas are often now classified by year and region of production.

Despite China's turbulent past in the 20th century, it is still possible to find pu'er that is 10 to 50 years old, as well as a few from the late Qing dynasty. Indeed, tea connoisseurs and speculators are willing to pay high prices for older pu'er, upwards of thousands of dollars per cake.

Pu'er tea is typically available as loose leaf or as cakes of compacted tea.

Introduction and history

Pu'er tea is traditionally made with leaves from old wild tea trees of a variety known as "broad leaf tea" or by the scientific name, Camellia sinensis var. assamica, which is found in southwest China as well as the bordering tropical regions in Burma, Vietnam, Laos, and the very eastern parts of India. The shoots and young leaves from this variety of tea tree are often covered with fine hairs, with the pekoe (two leaves and a bud) larger than other varieties. The soil also causes slight differences in chemical composition, which alter the taste and smell of the brewed tea, as well as its desirability for aging. Due to the scarcity of old wild tea trees, pu'er made using such leaves blended from different tea mountains of Yunnan are highly valued, while more and more connoisseurs seek pu'er with leaves taken from a single mountain's forests.

Pu'er is well known for being sold as a compressed tea cake and that it usually ages well to produce a pleasant drink. Through this storage, the tea typically takes on a darker colour more mellow flavor. Often pu'er leaves are compressed into tea cakes or bricks, and are wrapped in materials such as cloth or paper, which when stored away from excessive moisture, heat, and sunlight mature the tea. The process of pressing pu'er leaves into cakes and aging the tea cakes possibly originated from the natural aging process that happened in the storerooms of tea drinkers and merchants, as well as on horseback caravans on the Ancient tea route, which was used to trade tea to Tibet and more northern parts of China. Compression of the tea into dense objects eased transportation and reduced damage to the tea.

Health

Drinking pu'er tea is widely reputed to aid in digestion, reduce blood cholesterol and lipid levels. It is also widely believed in Chinese culture to reduce the effects of heavy alcohol consumption and hangovers. In traditional Chinese medicine, the tea is believed to invigorate the spleen and inhibit "dampness." In the stomach, it is believed to reduce heat and "descends qi".

pu'er tea is widely sold as a weight loss tea or used as a main ingredient in such commercially prepared tea mixtures. Though there is as yet no empirically backed evidence as to how pu'er might facilitate weight loss, the tea does appear to help individuals lose weight. Widely proposed explanations include that the tea increases the drinker's metabolism, or that the high tannin content in the tea binds macronutrients and coagulate digestive enzymes, thus reducing nutrient absorption.

Production

All types of pu'er tea are created from maocha, a mostly unoxidized green tea processed from a "large leaf" variety of tea tree found in the mountains of southern Yunnan. Maocha often undergoes "ripening" for several months prior to being compressed to produce ripened pu'er (also commonly known as "cooked pu-er").  It can also be directly compressed to produce raw pu'er.

While unaged and unprocessed raw pu'er is technically a type of green tea, ripened or aged raw pu'er is sometimes categorised as a subcategory of black/red tea due to the dark red colour of its leaves and liquor. However, pu'erh in both its ripened or aged forms has undergone secondary oxidization and fermentation caused both by organisms growing in the tea.  This causes free-radical oxidation which provides health benefits. Thereby pu'er is a unique type of tea.

In China,  pu'er is classified as a black/red tea because it is fermented. This is often resented by tea aficionados who argue for a separate category for pu'er as most other black/red teas tend to be of lower standard and status.

After picking appropriate tender leaves, the first step in making raw or ripened pu'er is converting the leaf to maocha, or literally "light green rough tea" or "rough tea" respectively. Plucked leaves are handled gingerly to prevent bruising and unwanted oxidation. The leaves are then spread out in the sun or a well ventilated space to wilt and remove some of the water content. If the weather is uncooperative, such as cloudy or rainy, the leaves will be wilted by lightly heating in a frying pan. This difference in processing that will affect the quality of the resulting maocha and pu'er. The wilting process may be skipped altogether depending on the tea processer.

The leaves are then dry pan-fried using a large wok in a process called "kill green," which halts enzyme activity in the leaf and prevents further oxidation. With enzymatic oxidation halted, the leaves are rolled, rubbed, and shaped into strands. The shaped leaves are then dried in the sun and then manually picked through to remove bad leaves. Once dry, maocha can be sent directly to the factory to be pressed into raw pu'er, or to undergo more processing to make ripened pu'er. Sometimes maocha is aged uncompressed and sold as aged loose-leaf raw pu'er.

Raw pu'er tea, also known as "uncooked pu'er" or "green pu'er," is simply maocha tea leaves that have been compressed into its final form without additional processing.

Ripened pu'er tea is pressed maocha that has been specially processed to imitate aged raw pu'er. Even though it is more commonly known as "cooked pu'er," the process does not employ cooking to imitate the aging process.

The process used to convert maocha into ripened pu'er is a recent invention that manipulates conditions to approximate the result of the aging process by prolonged bacterial and fungal fermentation in a warm, humid environment under strict conditions.  This technique is called "wet piling," which involves piling, dampening, and turning the tea leaves, a process similar to composting.

The piling, wetting, and mixing of the piled maocha creates even fermentation.  The bacterial and fungal cultures found in the fermenting piles were found to vary widely from factory to factory throughout Yunnan, consisting of multiple strains of Aspergillus, Penicillium, yeasts, as well as wide range of other microflora. Control over the multiple variables in the ripening process, in particular humidity and the growth of Aspergillus, is key in producing high quality, ripened pu'er. Poor control in fermentation/oxidation process can result in badly ripened pu'er, characteristics include: badly decomposed leaves and a flavour and texture of compost. The ripening process customarily takes anywhere from half a year to one year. As such, a ripened pu'er produced in early 2007 will be pressed in the winter of 2007/2008, and appear on the market between late 2008 or early 2009.

This process was first developed in 1972 by Menghai Tea Factory and Kunming Tea Factoryto imitate the flavor and color of aged raw pu'er. This technique was an adaptation of "wet storage" techniques that were being used by merchants to falsify the age of their teas. Mass production of ripened pu'er began in 1975. While it can be steeped without further aging, it can also be stored to "air out" some of the less desirable flavors and aromas acquired during fermentation. The tea is often compressed but is also common in loose form. Some collectors of pu'er believe that ripened pu'er should not be aged for more than a decade.

To produce pu'er many additional steps are needed prior to the actual pressing of the tea. First, a specific quantity of dry maocha or ripened tea leaves pertaining to the final weight of the bingcha is weighed out. The dry tea is then lightly steamed in perforated cans to soften and make it more tacky. This will allow it to hold together and not crumble during compression. A ticket, called a "Nei fei" or additional adornments, such as coloured ribbons, are placed on or in the middle of the leaves and inverted into a cloth bag or wrapped in cloth. The pouch of tea is gathered inside the cloth bag and wrung into a ball, with the extra cloth tied or coiled around itself. This coil or knot is what produces the dimpled indentation at the reverse side of a tea cake when pressed. Depending on the shape of pu'er being produced, a cotton bag may or may not be used. For instance, brick or square teas often are not compressed using bags.

Depending on the desired result, from quickest and tightest to slowest and loosest, pressing can either be done by:

    * A hydraulic press that forces the tea into a metal form factor, which is on occasion decorated with a motif in relief. Due to efficiency, this method is commonly used to make all forms of pressed pu'er. Tea can be pressed in the press with or without it being bagged. Tightly compressed bing, formed directly into a mould without bags using this method are known as "iron cake/puck" due to its density and hardness. It is believed that the taste of densely compressed raw pu'ers can benefit from careful aging for up to several decades.
    * A lever press, which was operated by hand for tight pressings. It has largely been replaced by the modern hydraulic press.
    * A large heavy stone, carved into the shape of a short cylinder with a handle, weighs a bag of tea down onto a wooden board. The tension from the bag and the weight of the stone together gives the tea its rounded and sometimes non-uniformed edge. Because of the manual labour involved, this method of pressing is often referred to as: "Hand" or "Stone-pressing," and is how many artisanal pu'er bing are still manufactured.

Pressed pu'er is removed from the cloth bag and placed on shelves where they are allowed to air dry.  Depending on the wetness of the pressed cakes may take several weeks or months. The pu'er cakes are then individually wrapped by hand, and packaged in larger units for sale.

Classification

Aside from vintage year, pu'er tea can be classified in a variety of ways: by shape, processing method, region, cultivation, grade, and season.