Pu-erh Is a New Old Kind of Tea

A cake of Pu-erh tea http://en.wikipedia.org/wiki/Pu-erh_tea Photographer: Jason Fasi

Many customs prevail elsewhere but not here, and some have much to offer. Take tea, for instance. It’s by far the most widely consumed beverage on earth (not counting water), but you wouldn’t know it by looking around America, where coffee rules. We’re not against coffee, but when it comes to health benefits, nothing matches tea—true tea. By that we mean tea made from leaves of the tea tree, Camellia sinensis, which is native to China. We have nothing against herbal teas either, but they are, for the most part, lightweights in the health department.* This article is about a tea heavyweight—one that may, ironically, help turn “heavy” to “light.”

*Herbal “teas” are not teas at all—they’re herbal infusions, for which the proper term is tisane (pronounced tih·ZAHN; from the French term for barley water).

We Can Chew the Fat about Tea . . .

Teas come in a welter (but not welterweight) of names—there are about 3000 known varieties. This obscures the fact that there are, by most accounts, only four basic kinds of tea: white, green, oolong, and black. White tea, the rarest, is a delicate tea made from the tree’s young buds (the lower-quality whites also include some leaves), whose downy, silvery hairs make them appear white in the sunlight; the buds are processed with no fermentation.

The other three teas are made from the tree’s leaves, but with different degrees of fermentation (an oxidative process) before they’re dried and packaged. Like white tea, green tea is made with no fermentation, and it has a grassy freshness that holds great appeal. Oolong tea is made from partially fermented leaves and is considered by many to be the “champagne” of teas. Black tea is made from fully fermented leaves and has a stronger character (and darker color) than the others. In these different processing methods lie important differences in the chemical composition, and hence the medicinal qualities, of the teas in question.

. . . But Pu-erh Can Suppress the Fat

All other names associated with true teas pertain to regional varieties, or to production or blending methods, of Camellia sinensis, and all are made as one (or more) of the white, green, oolong, or black kinds of tea. A tea that is popular in China but not yet well known in the West is an exotic variety called Pu-erh.¹ Our interest in Pu-erh lies in its health benefits, especially its ability to suppress fatty acid synthesis, which can help in preventing weight gain and thus obesity. We’ll return to that after an overview of what Pu-erh is and how it’s made.

Pu-erh is an extraordinary kind of tea, as explained in the sidebar, “An Aged Tea?” (now is a good time to read it). Most tea names are derived from their place of origin or principal growing region (Darjeeling, e.g., is a town in northeastern India), and Pu-erh is no exception: it denotes a regional varietal, but also a processing method that is unique to this type of tea. The potential for confusion is magnified when we try to decide which of the four basic kinds of tea Pu-erh “belongs to,” i.e., which kinds it is made as. The answer is three: green, a sort of black, and another sort of black. Hunh? Please be patient, and we’ll sort this out.

An Aged Tea? In the Yunnan province of southwestern China, there is a town called Pu’er, near the borders of Vietnam, Laos, and Myanmar (the former Burma). A major product from this region is Pu-erh tea (as with the wines of Europe, it’s common to name teas for their place of origin). The history of Pu-erh tea can be traced back about two millennia to the Han dynasty, and to this day, the tea is very popular in China and some other parts of the Orient.* *Pu-erh, by the way, is pronounced poo·air, which is unfortunate enough; please don’t make it worse by saying pew·air. Like wines, teas differ widely for many reasons, including where and when they were grown, as well as the cultivation, harvesting, production, packaging, and storage methods used. A major factor, of course, is the tea’s botanical variety (called varietal in wine-speak). Varietals of the wine grape Vitis vinifera, for example, include Chardonnay, Zinfandel, and dozens of others from which almost all white, rosé, and red table wines are made, as well as sparkling wines and dessert wines. Pu-erh tea is made from a broadleaf varietal of the tea tree called Camellia sinensis var. assamica (there are many local subvarietals), which is prevalent in the mountains and valleys of Yunnan province. The Chinese call it dà yè. The plant’s pekoe (the bud and its two surrounding leaves) is larger than that of most other varietals, and its leaves have a somewhat different chemical composition, giving Pu-erh a distinctive aroma and flavor profile. Remarkably, the chemical composition also makes the leaves suitable for aging to enhance the quality of the tea (other teas do not age well and are best drunk as young and fresh as possible). Many Pu-erhs have been aged for several decades, and some even for up to a century, since the time of the last Chinese dynasty (Qing), which ended in 1912. The environmental factors that affect the aging are much more diverse and variable than those for wine and are critical to the teas’ proper development. © iStockphoto.com/Oliver Benjamin The tea leaves are graded on a ten-point quality scale, and the products are also usually identified by such factors as the year and season of harvest and, of course, the regional source. Much value is placed on favorable terroir (a term well known to wine lovers), which means the “essence of a place”—the combined effects of its topography, soil, microclimate, cultivation practices, etc. Also of great importance is the tea factory (akin to a winery) where the leaves are processed and compressed into “cakes” of various sizes and shapes. Most cakes weigh anywhere from about half a pound to a few pounds. Especially prized are hand-processed Pu-erh teas harvested in the spring from the wild forests of the “Six Famous Tea Mountains” in Yunnan.* As with wines, though, the quest for the ultimate tea is made more difficult by the many fakes on the market—buyer beware! *Among the local subvarietals of Pu-erh is one called zĭjuān (“purple lady”), whose pekoes have a purple hue. For a remarkable health angle on the color purple, see the article “Purple Corn Color May Help Prevent Obesity” on page 16 of this issue. The last few years have seen the rise of a new generation of tea factories employing advanced technologies, high-quality mass production methods, and modern marketing techniques to transform Pu-erh from a traditional regional specialty to a product for the global market. We can expect to hear much more about Pu-erh in the coming years.

1. Green Pu-erh, aka Raw or Uncooked Pu-erh

All Pu-erh teas are produced from máochá, or freshly harvested tea leaves that have undergone little or no oxidative fermentation by the plant’s own enzymes. To make green Pu-erh, the máochá is heated to arrest enzymatic activity, and the withered leaves are then rolled, dried, and graded. This kind of green Pu-erh is commonly called “raw” or “uncooked” (sheng in Chinese).

Like any other green tea, the green Pu-erh can be (and is) sold as loose leaves for immediate consumption. The leaves can also be allowed to age for brief periods before consumption. Typically, though, the better grades of leaves are lightly steamed and then compressed into cakes of various sizes and shapes so the raw tea can age for a few years—or for many years, or even decades. This produces a different, and potentially great, type of Pu-erh—no longer green—that’s known by a couple of clunky names, namely . . .

2. Aged Raw Pu-erh, aka Secondary Oxidation/Fermentation Pu-erh

During the aging of green Pu-erh, a so-called secondary oxidation/fermentation occurs—slowly—owing to the yeasts and other fungi infecting the tea. Some of these microbes are there to begin with, and others appear later. By altering the chemical composition of the tea, they play a crucial role in developing its sensory characteristics—and its health benefits.

The secondary oxidation, together with a certain amount of microbial fermentation, allows the tea to mellow and improve in quality. Indeed, it can improve greatly if everything is done right and Lady Luck is smiling. (As with fine wines, however, much can go wrong, foiling the best-laid plans.) At its best, this “aged raw Pu-erh,” or “secondary oxidation/fermentation Pu-erh,” is said to be unmatched by any other kind of tea. It’s the most highly prized of all by tea connoisseurs and speculators, some of whom are willing to pay up to thousands of dollars for individual cakes, to be stored in climate-controlled tea cellars—and perhaps even to be consumed someday (reverently, of course).

In the process described above, the Pu-erh changes from a green tea to what can be considered a black (fully fermented) tea. It’s not generally called black, however, because that name is usually reserved for another kind of Pu-erh—the third major kind—which also has several other names.

3. Black Pu-erh, aka Ripened, Fermented, or Cooked Pu-erh

This much more affordable tea is by far the most popular type of Pu-erh currently on the market. Like green Pu-erh, black Pu-erh starts out as máochá, and the processing is essentially the same through the heating, rolling, drying, and grading of the leaves. (Right away, we know this is no conventional black tea: in making that kind of tea, the leaves are not heated, because that would prevent the natural enzymatic fermentation, thus defeating the purpose!)

Worker grading tea

Compressing a cake

This process is akin to composting. It requires great care, because overdoing it can spoil the tea, producing a variety of unpleasant flavors, including one that’s said to be reminiscent of . . . compost. (But how would you know that, unless you had actually eaten compost?)

After a few months to a year of this accelerated aging, the black Pu-erh should have a pleasantly earthy quality. It’s sold as loose leaves for immediate consumption or, like green Pu-erh, it’s steamed and compressed into cakes for further (slow) aging for a few years. Although black Pu-erh can age well for up to a decade, connoisseurs say that it falls far short of the superb characteristics of aged raw Pu-erh. It does, however, appear to share with that tea the advantage of providing special health benefits, owing to the microbial action on chemical compounds in the leaves.

In addition to “black,” this product is known variously as “ripened,” “fermented,” or “cooked” (the last being a misnomer, as no cooking is involved). The Chinese call it shou, which they classify as a black tea. Purists disapprove of that, however, because Pu-erh is not made by the same method as conventional black tea and because in China, the latter tends to be looked down on as somewhat inferior—the Chinese much prefer green tea. (To further confuse matters, what we call black tea because of the color of the leaves, the Chinese call red tea because of the color of the brew. How do you write “headache” in Chinese?)

The Medicinal Properties of Tea . . .

In a paper published in 2005, researchers in Taiwan opened with this slightly clumsy but provocative sentence: “It is generally observed that obese people are seldom found in the long-term tea drinking individuals group.”² The authors were presumably referring to the Chinese population, but let’s assume that the statement holds generally. The relative absence of obese people among tea drinkers does not, of course, prove that drinking tea prevents obesity—there could be other explanations for the negative correlation, such as: tea drinkers are the kind of people who eat less fat or get more exercise than those who don’t drink tea.

The authors’ observation jibes, however, with much evidence acquired in recent years suggesting that tea does indeed reduce lipid levels and inhibit obesity, along with its many other well-documented health benefits. These benefits are attributed mainly to the teas’ polyphenolic compounds and are described by the Taiwanese researchers as: antifungal, anti-inflammatory, antioxidative, antimutagenic, anticarcinogenic, and antitumorigenic, as well as lowering plasma cholesterol and triglyceride (fat) levels and reducing blood pressure and platelet aggregation (the tendency to form blood clots).

. . . Include an Antiobesity Effect

Wow—that’s quite a résumé for such a humble brew, and it supports the belief of some scientists that tea is the most healthful of all foods and beverages. But what kind of tea should one drink? The four major kinds—white, green, oolong, and black—all have some biologically active constituents in common, but they also differ substantially in regard to some others.

Whether one regards Pu-erh tea as belonging within those four categories (as many do) or as a separate category unto itself (as some do), it has a unique spectrum of chemical constituents that may have particular value for certain purposes. Chief among these may be the prevention of weight gain and obesity, as we will see in detail in next month’s issue (we’ve run out of space for it here—sorry!). Meanwhile, a caution: Pu-erh teas differ greatly: not all have the same anti-fat effects. One must choose carefully for that, or risk being disappointed by ineffective products.

Pu-erh—Exotic but Affordable

Just as the great majority of red wines do not age well for more than a few years (most whites do not age well at all, and were never intended to), most Pu-erh teas also do not age well for more than a few years. Like their wine counterparts, Pu-erhs that age gracefully for many years or decades acquire mythical status—with prices to match. Fortunately for us, there are plenty of moderately aged, reasonably priced versions to enjoy and benefit from.

References

1. Reliable information on Pu-erh tea is hard to come by in English (and we don’t read Chinese). Much information on Pu-erh on the Web is highly unreliable. Most of the general (nonmedicinal) information in this article comes from the Wikipedia entry “Pu-erh tea” (as of April 30, 2007), which appears to be reasonably well researched. Another site worth looking at is www.pu-erh.net.
2. Kuo KL, Weng MS, Chiang CT, Tsai YJ, Lin-Shiau SY, Lin JK. Comparative studies on the hypolipidemic and growth suppressive effects of oolong, black, pu-erh, and green tea leaves in rats. J Agric Food Chem 2005;53:480-9.