Dark tea, waiting for time to pass

Dark tea, the most popular of which is Pu Erh, is a type of tea that remains unknown to many tea enthusiasts. Known as dark tea, aged tea or fermented tea, it improves as it ages, a characteristic it owes to its mode of production, which involves fermentation.

By Laetitia Portois

After harvesting, the leaves used to make Pu Erh are left to wither in the sun for 24 hours.

The history of dark tea dates back to the seventh century, but for many years it remained in obscurity before it became the subject of a craze and intense speculation in modern times. It is a mysterious tea which develops its aromas and flavours over the years. The first records of dark tea date back to the Tang dynasty, at the beginning of the seventh century. At the time, tea was used as a condiment, among other things, in particular to season soup.

Dark tea started with the cake

As a daily commodity, Pu Erh needed to be transported quickly throughout China. How was it possible to preserve it and transport it in sufficient quantities on mules over such long distances? This was an important issue, because at the time tea was used as a currency to exchange for horses in Tibet, where it was consumed as a vegetable as part of the Tibetans’ meatheavy diet. This is how the tea route was born. At the time, the Chinese had the ingenious idea of compressing the leaves into cakes so they could be easily stacked and stored. This method also limited the leaves’ contact with the air and considerably slowed down their oxidation in transit. Fortuitously, they realised that the tea would ferment naturally on these long journeys, developing unique flavours. This marked the origin of the Pu Erh cake, a form still used today for shaping dark teas.

For centuries, dark tea was carried by mules along the ancient tea and horse route (between Yunnan and Tibet and to the steppes of Russia) as a trading currency for nomadic merchants. But in 1391, the emperor told tea-producing regions to stop sending tea in the form of compressed leaves to the imperial court. He preferred to receive loose leaves, so producers began making leaves in many colours. Dark tea nonetheless continued to be traded, though in dwindling volumes. Yet extensive expertise was poured into these quality teas that became more refined with the passing years …

Dark teas, fermented teas

It is the production method and ageing process that characterise dark teas. These are the only teas that undergo fermentation. The leaves are harvested and processed at different times. This means that the same leaves will produce two different dark teas using two different methods. However, both are created through fermentation of the same tea: Mao Cha.

Raw and cooked Pu Erh

A distinction is made between raw Pu Erh, known as “Sheng”, a Mao Cha compressed into a cake and left to age, and cooked Pu Erh, known as “Shu”, for which fermentation is artificially accelerated.

The first steps in the production of Shu and Sheng are identical: the freshly picked leaves are fired in a wok (10 to 20 minutes) to partially fix the oxidases (enzymes that stop oxidation). The tea is then rolled and dried, usually in the sun. The difference lies in the ageing process, which is long and natural for Pu Erh Sheng, and accelerated for Pu Erh Shu.

To compress Pu Erh, the dry leaves are steamed for a few minutes then placed in a cotton bag and crushed between the plates of a press to form the cake. This is left to dry on a rack for 24 hours, then packed in rice paper. The cakes are sometimes bought by a merchant and “laid down” to age for years to obtain a Pu Erh Sheng. It is during this stage that the post-fermentation process takes place: microorganisms in the leaves cause them to oxidise naturally when kept in a humid, well-aired place. This reaction

PU ERH OR DARK TEA?

Pu Erh owes its name to the city of the same name. The place was once the starting point of the tea route and an important trading post for tea. Today, only dark teas produced in this region can claim the “Pu Erh” designation of origin, which has been legally defined since 2003 as a “tea produced using leaves picked from Da Ye large-leaf tea plants grown in Yunnan, dried in the sun and fermented using the natural or artificially-induced process”. 1 At Palais des Thés, we have chosen to continue to use the name Pu Erh for teas that follow the traditional process established in border countries. So, for example, you’ll find a Pu Erh Shu from Vietnam in our stores.

is caused by the beneficial bacteria naturally present in the leaf, which secrete enzymes that alter the chemical properties of the leaf. As the years pass, the cake develops specific aromas. Some raw Pu Erh cakes can be consumed after a short period of ageing. As with wine, if you like the flavours of a young wine, there is no need to wait ten years before drinking it. Others are kept in cellars for many years before being sold. With Pu Erh Shu, the ageing process is artificially accelerated using a method invented in the early 1970s to meet growing demand. Mao Cha is spread out on the ground and sprayed with water, then covered with a cloth. The temperature rises quickly, reaching 60°C inside the bed of tea. Microorganisms grow and mould appears. Once the desired degree of fermentation has been achieved, the leaves are spread in a thin layer and dried naturally for two weeks. These teas are easy to store and can be consumed immediately.

A forest walk

Pu Erh teas are incredibly fragrant. They evoke wood and undergrowth, leather and damp straw. Predictably, raw and cooked Pu Erh develop quite different notes. A young raw Pu Erh (after five years of being laid down) has a subtle astringency, reminiscent of the smell of a forest after the rain, with scents of freshly cut grass, stones and earth. With repeated brewing, it reveals subtle mineral, fruity notes. Cooked Pu Erh is more direct, more woody, almost animal. Notes of leather, mushrooms, moss and waxed wood mingle harmoniously, supported by subtle vanilla and caramel scents. It is much rounder, perfect for sipping by the fire on a winter’s day. •

Hear about dark tea

To learn more about dark tea, check out our podcast, Un thé, un voyage (in French). FrançoisXavier Delmas, founder of Palais des Thés, takes us on a journey along the ancient tea route. He offers some treats for the palate with some incredible tea tastings.

PU ERH, AN OBJECT OF SPECULATION

In 2007, A Pu Erh craze took off in China. In the space of just a few weeks, the tea became subject to intense speculation. In 2013, some cakes sold for more than €1,000 at the Canton tea fair. Pu Erh Shengs are very popular: collectors and tea enthusiasts invest in relatively young cakes they hope will gain in value with age. Others buy these teas solely for speculative purposes, as is the practice in the world of wine.

For millennia, Chinese medicine has valued Pu Erh for its digestive and purifying benefits. We like to enjoy the tea with foods of character such as parmesan, aged Cantal cheese and game. Your guests will be intrigued when you serve tea with a meal instead of wine!