Discovering the mysteries of Pu Erh©

by David Kilburn

Almost ten years ago, I noticed a short newspaper story about the discovery of a very ancient tea tree in a mountain-top rain forest jungle, not far from the Myanmar border, in the Chinese province of Yunnan. There are many ancient tea trees in Yunnan, including some that are 1,000 or more years old. However, what was interesting about the new discovery was that it appeared far older than any yet known.

Later, the Chinese government announced that this was the world’s oldest tea tree, with an age of approximately 2,700 years. There are many problems in determining the age of very ancient trees since the core of their trunks usually decays, destroying the chronological record tree rings usually provide. Happily, modern science can help complete this record.

In January 2005 , we went on a pilgrimage to Yunnan to visit this ancient tree which we eventually reached after almost a day of climbing and trekking in the mountains. With a height of over 25 meters, the tree is a mysterious and majestic sight, still in good health, and bearing leaves though these are not harvested for tea production (A single, hand-sized leaf from this tea tree is on display at the Tea Museum in Daikanyama).

Like other tea trees in Yunnan, this ancient giant bears long, broad leaves (as indeed do many other species of rain forest trees), quite unlike the smaller leaves that grow on tea bushes in today’s tea plantations.

The old tea trees of Yunnan are our closest link to the origin of the tea plant, Camellia Sinensis. It is also their leaves that are the source of the remarkable qualities of Yunnan’s most famous tea, Pu Erh.

Like other kinds of Tea, Pu Erh has long been considered good for health. However, over the centuries, it has acquired a reputation for helping to eliminate fats and purify the body. To some extent, these old claims are supported by modern medical research.   

The tea is named after an old market town which used to be the regional centre for tea growers, traders, and merchants to do business. Today, Pu Erh is a modern Chinese town that has little to suggest its long history. However, near the town, you see the start of the “Old Horse Road” which provided the route for merchants to transport tea to Tibet, and Russia, packed on the backs of horses.

The problems of transporting tea over these long arduous journeys also played a role in the development of Pu Erh tea. Even packed tightly into sacks, loose tea leaves were far too bulky to transport long distances, in great quantities, on the backs of mules. Accordingly, tea makers compressed the tea in to cakes and bricks to enable greater quantities to be carried.

During the long journeys, the compressed tea underwent a very slow fermentation, changing in colour and taste to the dark coloured, warm taste that is characteristic of Pu Erh tea. We do not know quite when tea growers and traders realised the nature of these changes, but it was a very long time ago since there are written records about the tea dating from over 1,700 years ago.

Until modern times, Pu Erh tea was always made via the slow fermentation of compressed blocks of tea – not necessarily on the backs of mules – the tea was also aged in this way by the growers themselves who would store it so that the special character of the tea would naturally develop under their control. From experience, tea makers learned that it took about three years for a compressed block of green tea to be naturally transformed into Pu Erh. They also discovered that the flavour could continue to develop slowly with longer storage but that there was usually very little change after about ten years, though that ultimately was a matter of personal taste.

Manufactured in this lengthy way, the supply of Pu Erh was always limited and could not be increased quickly if demand increased.

Growing demand for Pu Erh tea from the 1950’s onwards led to the development of new techniques to hasten tea production. Rather than waiting three years or so, manufacturers eventually found they could create Pu Erh in a matter of months by accelerating the fermentation. Basically, the new technique involves sprinkling heaps of dried tea leaves with water and allowing them to ferment in a warm, humid atmosphere.  Today, most of the Pu Erh that comes to market is made this way. Depending on the quality of the tea leaves and the skill of the manufacturer, the quality Pu Erh made in this way can be comparable with that from traditional techniques or very crude. The difference is only revealed by tasting the teas.

Consequently, although there are large quantities of Pu Erh up to ten years old, the quantities available of older Pu Erhs quickly decline since their production was more limited. You can still find Pu Erh cakes made 20, 30, or even 40 years ago but beyond that age, anything is exceedingly rare and may not even be drinkable. Just as old wines can eventually turn into vinegar, old teas can also decay into dust.

Age has become a powerful tool in the marketing of Pu Erh teas. Older teas fetch much higher prices than younger ones since they are scarcer and their flavours more fully developed. Sadly, this has led to widespread fraud and fakery since some unscrupulous dealers exaggerate the age of their teas. Some may point to the aged Chinese paper wrappers on the teas as a proof of age, but these can be reproduced quite authentically by many printers in Yunnan and cannot be taken as definite proof of anything. There are also manufacturers who mix cheaper tea leaves from elsewhere with leaves from Yunnan.

Claims that a tea is a century old should certainly be treated with great suspicion. Two years ago, 140 grams of Pu Erh dating from last years of the Qing Dynasty was found stored among the personal effects of a Chinese scholar who died in 1968. Tea experts validated the age and said the tea was still drinkable. Eventually, the tea was auctioned for over US$25,000. The discovery of very old teas tends to be a headline news story whether the teas are drinkable or not.

If the age of the tea is very important to you when buying, then it is worth asking the vendor some questions. Exactly where was the tea made? Who was the tea maker? Where was it aged? How did the vendor obtain it? If the tea was obtained via a wholesaler, who were they and where? The answers should help in deciding how reliably the age of the tea might be known.

The true quality of a tea is revealed neither by the price paid nor the packaging but only in the appearance of the tea and its taste.  

When you examine a cake of good quality Pu Erh, you should not see any twigs, or mould spots (white or dark) on the surface. The leaves should ideally be whole, visually distinct. The leaves may be dry and fragile, but not powdery. Good tea is often quite fragrant, even when dry. When you examine the leaves after brewing the tea, whole leaves should be easily visible and you should be able to pick these out of the wet spent tea. There should be only a limited amount of broken fragments, no twigs, nor fruits of the tea plant in the spent tea leaves. The characteristic tea leaves from Yunnan are long and broad and with a saw tooth edge, you should be able to see these characteristics in the spent leaves. If the leaves also have thick veins then the tree is very likely an old one, and possibly a wild tree.

One way to be very sure of the quality and age of what you are buying is to purchase newly made cakes of compressed green tea from Yunnan and to age these yourself. You would need to store them at constant temperature in a slightly humid environment, away from strong smells and sunlight and wait at least three years for the cakes to develop their Pu Erh characteristics. There is a similarity with the wine drinker who buys young wines inexpensively and stores them in his cellar so that their character may develop over the years.

The most highly esteemed Pu Erh teas come from wild, trees 1,000 or more years old. These teas are rare because production is in very limited quantities. Next come teas made from ancient tea plantations that have returned to the wild. Many of the trees in these plantations are hundreds of years old and they have often been cared for by the same villages for many centuries. Of course there are also more recent tea plantations – on driving through Yunnan you can see hundreds of acres of new plantations created in recent years by major tea companies. These can all produce very high quality teas but without some of the subtleties of their more ancient brethren.

Buying tea while thinking only of the age or the price often leads to disappointment. Buying tea with an appreciation of the taste and quality leads to enjoyment and years of tea drinking pleasure.   

Tea in Daily Life

The tea plant has been an integral part of life among the tribal people of Yunnan for thousands of years. Wild tea trees grow adjacent to many villages and their leaves are used regularly in food and cooking in many different ways.

When a villager from the Aini people invites you home to drink some tea, he uses neither tea bags nor a tea pot. Quite likely, he will pick some leaves from a nearby tea tree, singe these in a fire, and then stuff them into a bamboo tube of water which he will boiled over the fire until the bamboo blacken from the heat. The result is an amazingly invigorating and refreshing drink!

Only a few species of bamboo are suitable for making tea in this way. Our host used Dragon Bamboo, which imparts a slight sweetness to the tea, as well as a hint of the bamboo itself.

Interestingly, elsewhere in Yunnan, there is a variety of Pu Erh made by packing the tea leaves tightly into bamboo tubes which are then roasted over a fire. When the bamboo itself starts to burn, the roasting is stopped and the cylinder of  bamboo-flavoured Pu Erh is removed and allowed first to cool then to mature.

Among the Bulang people, it is common to pickle tea leaves almost like Kimchi. Fresh tea leaves are cooked in water and then packed tightly into bamboo tubes with salt, chili, and spices. The tubes are then sealed with clay and buried in the ground for about two months. The pickled tea is used as a gift for special occasions and also forms part of the tribe’s regular diet. The people of Myanmar also prepare a pickled tea in a similar way.

One tea farmer, from the Jinuo tribe,  showed me how he prepared tea when working in the mountains. He too would pick some leaves from a nearby tea tree. He crushed these in his hands, added some leaves from a wild lemon tree and shook them up with some salt, garlic, and chili using water from a freshly flowing stream  - another surprising and tasty beverage.

There are many other flavours.  Elsewhere, you can find Pu Erh flavoured with Cinnamon or with a hint of citrus that comes from packing the tea inside the peel of bitter oranges.

The Jinuo also make hot tea using tubes of bamboo, much like the Dai people. When I asked the Jinuo farmer how many cups of tea he drank in a day, he answered: “Ah, it is impossible to count such a large number!”