Pu-erh tea is one of the most obsessed-over teas in the world – and one of the few that can improve with age.

Over the last decade, rapid modernization and rising incomes in China have made the production of labor-intensive artisanal teas like pu-erh far more costly. The quality of Chinese tea is also being impacted: by climate change, industrial farming practices and changes in production methods that favor quantity over quality.

For San Francisco-based tea master Roy Fong whose 45 metric tons of tea are slowly ageing in an atmospherically controlled warehouse, this means selling the pu-erh tea he bought in the 1990s back into the Chinese market.

The history of Pu-erh

From its beginnings, pu-erh tea has been esteemed. The very first book on tea, The Classic of Tea, written in the eighth century by Lu Yu who the Chinese sometimes call the “father of tea”, extols this tea’s virtue above all other varieties. Pu-erh gets its name from a city in the remote southern mountains of China’s Yunnan Province, but it can come from anywhere in those mountains where for two millennia tea has been grown and produced. Pu-erh-style teas have also been produced for centuries in the neighboring provinces of Guangdong, Guangxi, Sichuan, Hunan and in the border areas of North Vietnam, but in 2003 the Chinese government defined authentic pu-erh as coming solely from Yunnan. Tea plantations and wild groves are cultivated at altitudes of more than 1,500m/5,000ft and flourish in Yunnan’s warm, humid climate.

While the term “wild” is common in labelling, older tea trees are cultivated trees that were left unmanaged for years and now grow naturally. One of Yunnan’s largest ancient tea plantations covers more than 4,050ha/10,000 acres in the forests of the Jing Mai and Man Jung Mountains. Yunnan’s oldest tea trees are treasured as living fossils: one of the oldest trees on record, discovered in 1961 growing on the Great Black Mountain of Bada San, is 1,700
years old.

The cultivation of pu-erh tea in China dates back as far as the first century. As trade routes developed throughout Central Asia, tea was one of the first things to travel along them. As a Chinese proverb puts it: “Better to be deprived of food for three days than tea for one.” To make their tea easier to transport – it could take a year for a horse-drawn caravan to reach Tibet – the Yunnanese began compressing it into bricks, cakes, bowls and, later, into more fanciful shapes.These long treks to market also led to the discovery that the broad, tough leaves of pu-erh trees had a singular ability to improve over time, becoming earthier and more complex.

Eventually, the finest teas were intentionally aged to increase their value. By the 17th century, aged pu-erh was being sent as tribute to the Chinese emperors. Production and styles Pu-erh comes in two basic styles: raw, known as sheng, and cooked, known as shou. All tea starts as sheng, when green tea leaves are wilted, dry fried, rolled and sun-dried. Then, there’s the option of “cooking” the tea into shou, a process invented in the 1950s but popularised in the 1970s to imitate the long ageing process of raw tea. Today, cooked pu-erh is more popular than raw in Hong Kong.

The tea ferments in a warm, humid environment for up to one year, in a process that deepens and mellows the flavors and adds increasing amounts of complexity. Whether raw or cooked, at this point, the pu-erh – which has a distinctively astringent and tannic character – can be sold loose. Normally, however, it is compressed into cakes – or into bamboo stalks or even hollowed-out citrus fruit – and allowed to sit for years for what is essentially an extended microbial fermentation. Just as a wine can evolve over time, pu-erh flavors can change dramatically as the compressed tea and the beneficial fungi it harbors continue to interact.

Complex microbiome

Researchers have identified 390 fungal and 600 bacterial organisms in the microbiomes of raw and cooked pu-erh teas. The most commonly observed fungal taxa belong to Ascomycota and the most commonly observed bacterial taxa belong to Firmicutes, Actinobacteria, and Proteobacteria. Interestingly, fungal diversity drops and bacterial diversity rises as a result of raw or cooked fermentation. The composition of microbial populations changes significantly
among fresh leaves, and raw and cooked pu-erh.

The most sought-after tea, aged raw pu-erh, has a fungal population more like cooked than young raw pu-erh. This indicates that the accelerated microbial fermentation of cooked puerh results in a microbial community composition similar to that found in much older, raw pu-erh. It also provides an explanation for the rapid acceptance and widespread use of the cooked pu-erh process. Contrary to the beliefs of many collectors, ageing does not
significantly affect the communities of cooked tea, suggesting that ageing cooked tea is unnecessary.

Traditionally, ageing took place in mountain caves, but today most tea merchants use temperature- and humidity-controlled warehouses. It can take up to 30 years for a pu-erh to be considered fully mature – though some tea pros think it should not age for more than 15 years. When it reaches that point, the resulting brew tastes pungent and earthy, but also clean and smooth, reminiscent of the smell of rich garden soil or an autumn leaf pile and often with roasted or sweet undertones.

Despite its low profile, pu-erh is not a newcomer to the West; it most likely made its first appearance in America in the late 19th century with the wave of immigrants who arrived from China’s Canton province to build the railroads. Fong, who owns the Imperial Tea Court and operates tearooms in San Francisco and Berkeley, California, calls pu-erh the birthright of every Cantonese. “During my childhood years in Hong Kong, whenever tea was served, pu-erh was the automatic choice,” he says. “I think there would be violence if cooked [pu-erh] were ever banned in Hong Kong or southern China.”

Growing market

Fong, who markets his own brand of pu-erh as part of his San Francisco-based business, believes good-quality cooked pu-erh peaks at 20 years. “There is something magical that happens with shou after 20 years,” he says. “It becomes soft, smooth, silky and rich. Some teas can have delicate plummy and almond notes. They are still youthful and retain their floral qualities, but they are highly concentrated, with distinct layers of flavor.” However, pu-erh spent decades mostly confined to Chinese restaurants. But in 1993, when Fong opened his first San Francisco tea-house assuming that it would mainly attract Chinese expats, he was surprised to find most of his clientele was Caucasian.

Not only that, many were interested in pu-erh, and willing to pay market price for aged varieties. Most Westerners, if they’ve tried pu-erh at all, have only sampled poor-quality pu-erh. The tea’s pungent earthiness can be jarring for people who expect a delicate brew. Fong likens it to strong cheeses, or tannic
wines. Those who appreciate complex flavours, however, have ensured that interest in pu-erh has increased over the past decade.

Pairing Pu-erh

Pu-erh has also finally broken out of the dim sum houses. Alice Cravens, a former tea buyer for Chez Panisse restaurant in Berkeley, California, and other fine-dining restaurants, says pu-erh has pairing potential far beyond Chinese food – she likes to suggest it to restaurants that offer lots of wood-fired dishes, like grilled lamb. “Red-wine drinkers gravitate to the robust flavors and wine-like tannins of these rich, intense teas,” she says. “Pu-erh teas exhibit aromas and flavors that are found in wines like Pinot Noir: earth, forest floor, mushroom and even barnyard.”

Pu-erh has also made its way onto bar menus. The tea is a principal ingredient in drinks at New York hotspots like Pegu Club and the Flatiron Lounge. Brooklyn’s Marlow & Sons has offered various tea cocktails, including the Hot Iced Tea, made with pu-erh, orange bitters and whiskey that was infused with Himalayan long peppers. “The pu-erh tea really grounded the drink and gave it a smokiness that helped mellow the spiciness of the peppers,” says
bartender Johnny Edlund. “It worked out really well.”

There is a downside to this new popularity: as pu-erh’s profile has risen, so have prices. Vintage teas from the 1960s, known as “Masterpiece Pu-erh”, can command as much as $3,000 to $5,000 per cake. Then there are the people who, while honest, have come to appreciate pu-erh only as an investment, buying up choice cakes to age and sell for a profit later. “This scenario happened all over China,” says Fong. No matter what happens to prices, Chinese consumers seem thirstier than ever for pu-erh. More and more westerners are immersing themselves, drawn by the mystique, the ritual, the prestige and, above all, the flavor – that nuanced, earthy complexity that makes pu-erh unlike any other tea.