How Pu-erh Tea is Made - Part 1
Turning fresh leaves from a tea tree into a drinkable pu-erh cake involves many labour-intensive steps that need to be executed skilfully and under time pressure. Broadly speaking, pu-erh production can be separated into ‘rough processing’, which is the process of making loosely-finished tea (毛茶 máochá), and ‘fine processing’ which is turning the maocha into raw or ripe pu-erh.
This article outlines the steps involved in rough processing.
1. Picking tea leaves (采茶 cǎi chá)
Picking tea leaves (采茶 cǎi chá) is the first stage of ‘rough processing’ pu-erh tea.
Tea trees will sprout fresh growth when they have enough moisture followed by a period of uninterrupted sun. In Yunnan, the most ideal weather conditions for tea are in spring (March-May), followed by autumn (September/October).
Some producers will continue to produce tea throughout the monsoonal summer season, though the tea made during this rainy season is called as such (雨水茶 yǔshuǐ chá) and generally of low quality. No tea is made during winter, as picking tea plants year-round can be damaging to their longevity.
Once enough fresh leaves have sprouted they are quickly and skilfully picked by hand whilst they are still tender. For pu-erh tea, first four to five leaves including the bud are selectively picked.
Picking is both labour intensive and time sensitive as the leaves slowly begin to oxidise once they are picked from the tree, and must be further processed as soon as possible. This is why commercial plantations plant trees in dense rows that are pruned to form a ‘tabletop’ for maximum efficiency in picking, and are often next to major roads or with picking facilities on site.
On the other hand, picking old-growth tea trees requires significantly more effort both in the picking itself, and often accessing the growing areas themselves, usually pockets of forest growing on the mountainside, requiring hiking on foot in and out. The results are well worth it.
Picking leaves from old trees in the forest often requires a decent climb, sometimes several metres off the ground.
2. Withering the leaves (萎凋 wēidiāo)
Once the fresh leaves are picked, the clock starts ticking to get them back to a processing facility for withering (萎凋 wēidiāo) before unwanted oxidisation sets in.
Leaves that are squished in a bag or basket will start to bruise each other resulting in oxidisation. If left unattended, the pile of picked leaves will continue to oxidise and generate heat which further exacerbates oxidisation in a runaway cycle that can ultimately ruin the tea before any additional processing has occurred.
To prevent this oxidisation process from setting in, newly picked leaves are spread in a thin layer on bamboo mats or mesh-bottomed trays. The leaves are then left to cool down, slowly wilt or wither, and lose excess moisture in preparation for further processing.
The leaves here are about to be spread out by hand until they form a thin layer.
3. ‘Kill-green’ (杀青 shāqīng) or stir-roasting leaves
After withering, the leaves undergo a further process called ’kill-green’ (杀青 shāqīng). Here the wilted leaves are stir-roasted by hand in a cast-iron wok that is most commonly heated by firewood.
Once the woks have reached the correct temperature, a batch of leaves are tossed repeatedly to remove water content and to develop flavour and aroma. Stir-roasting is a crucial step in pu-erh production as the wok heat denatures (i.e ‘kills’) most—but not all—of the enzymes responsible for oxidation.
When stir-roasting leaves meant for raw pu-erh, a small amount of enzymes are deliberately left to remain. Over time and through proper storage, these enzymes along with bacteria and fungus, will ‘age’ the raw pu-erh in a process known as microbial ripening.
Frying tea by hand in this way requires a high degree of technical skill and practical knowledge of pu-erh production. Leaves that are over-fried will lose their raw pu-erh character and become essentially a green tea, whereas under-fried leaves can lead to an underdeveloped, overly sour and watery tea. There are machines that can be used for this step but they are generally considered inferior. In our own experience, hand-frying tea is the only way to go.
Pu-erh leaves being fried by hand, slowly losing moisture.
4. Rolling tea leaves (揉捻 róuniǎn
Once the stir-roasted leaves have cooled down, they undergo rolling (揉捻 róuniǎn).
Up until this point, the leaves are still tough, fibrous, and not very soluble in hot water. Rolling helps to break down the leaves’ cellular structure and release flavour and fragrance when they are eventually infused in hot water via brewing.
Rolling can be done by hand or machine. In our opinion, this is one of the steps where using a machine is often superior, and the vast majority of tea producers use them. A surprising amount of force needs to be consistently applied in order to effectively soften the leaves, which is difficult to do by hand especially for a large amount of tea.
Under-rolling often leads to a weak and poorly developed tea and over-rolling will yield tea that tends to brew intensely in the initial steeps, but loses flavour quickly in successive steeps. Tea that has been sufficiently rolled will release fragrance easily when brewed, and will produce an even and evolving flavour profile across multiple successive steeps.
The leaves here were rolled by hand and straightened into bundles for drying.
5. Sun-drying the leaves (晒干 shài gān)
Sun-drying (晒干 shài gān) is arguably the most critical step in pu-erh tea production, as it’s part of what allows the tea to age. Sun-drying relies on good weather, sufficient space and a decent amount of labour.
According to most technical definitions, sun-drying is a requisite part of pu-erh production; in order for a tea to be ‘pu-erh’ is has to have been sun-dried. Sun-dried tea leaves will retain small amounts of enzymes and moisture which will contribute to the overall characteristics of raw pu-erh tea; its flavour, fragrance, and ongoing ripening over time when stored in favourable conditions.
On the other hand, teas that have been dried in a machine often yield a distinct ‘green tea’ fragrance and flavour; the drying process has gone too far, likely killed off any remaining enzymes, and the tea is no longer raw pu-erh.
Our own experience in the field matches this—we’re of the opinion sun-drying is non-negotiable when it comes to producing quality pu-erh teas.
Greenhouses are often built to accelerate the drying process and protect the leaves from unexpected spring rain and visitors (i.e birds and bugs).
6. Removing the huangpian (黄片 huángpiàn)
After drying in the sun, leaves undergo further processing by hand in order to remove 黄片 (huángpiàn) or ‘yellow leaves’ – the larger, older, and discoloured leaves that are deemed visually unappealing and inconsistent in overall quality.
Huangpian is removed in order to improve the visual appearance and material consistency of a pressed tea cake. Historically, sorted huangpian were kept by farmers to drink for themselves as the material was considered too low value to sell. In recent years - as old-growth forest tea has increased significantly in value - huangpian are sold to savvy drinkers looking to drink expensive material on a budget.
Brewed by itself, huangpian has a soft, mellow, and sweet flavour as well as a lower amount of caffeine. We’re big fans of high-quality huangpian.
Huangpian being removed by hand from a batch of freshly sun-dried tea leaves.
7. Roughly finished tea (毛茶 máochá)
At this point, the tea has finished the rough processing stage, and is now called maocha. From here, the maocha can be drunk as a fresh tea, though by and large it will go through additional fine processing—destined to be compressed into a raw pu-erh to be aged and drunk, or put through a wet-piling fermentation process to produce ripe pu-erh.
Discover the process of turning maocha into a pressed pu-erh cake in our blog post Part 2 here.