Related to writing a tea blog and helping run a Facebook tea group I talk to lots of interesting people about the subject, recently William Osmont of Farmerleaf.  I’ve reviewed some very nice teas from them, different Yunnan Dian Hong black tea versions (here and here), a Moonlight white, and of course pu’er.

Farmerleaf, William buying tea leaves

This article is about his background in producing tea, and about typical questions that come up related to that area, about sub-regional variations, production and sourcing issues, and pu’er aging/fermentation.  In particular vendor marketing claims about Yunnan tea tree ages have been a source of controversy, related to some being disputed on social media, and William offers his opinions on the effect of tea tree age on tea character and about identifying tree ages.

How did you get started on an interest in tea?

“It all started on a sunny afternoon in French Provence.  With two friends we were hanging out in the streets of our little town, and we stumbled upon a newly opened tea shop. We tried different flavored teas, and I really loved the different tastes. I hadn’t paid much attention to tea until then. I drank flavored tea for a couple of months and then got into Darjeeling, Chinese green tea, African black tea… until I tried a 1998 ripe Pu-erh tea. I clearly remember that first session with Pu-erh tea, and from that time, I knew I would dedicate my life to this beverage.

After high school, I went to Yunnan for a year, in pursuit of better teas. That was the best year of my life, I was 19 and free to explore. I studied Chinese in Kunming for six months and then moved to the South of Yunnan, in Xishuangbanna. I would visit one or two tea mountains every week, learning about the taste of tea and the different processing method.

One day, as I was visiting Jingmai, I met a beautiful Dai girl named Yubai, who had only started her own tea factory that year. We fell in love, and she is now my wife.

In a fair deal with my parents, I would return to Europe and go to university after one year. I was really interested in biology and ecology. I wanted to go back to China as often as possible and start something in tea. In 2012, I opened an online tea shop ( in which I sold mainly Pu-erh teas from farmers I had met. A large part of it was made by my girlfriend in Jingmai. This little website allowed me to put a foot into the tea business and I am really grateful to the customers who trusted us for all those years. The profits allowed my girlfriend and me to meet every summer holiday in China, strengthening our love and expanding our tea network in Yunnan.

I graduated in 2016 and obtained a master’s degree in agricultural development. Yubai and I are now married, and we live in Yunnan for good. We have started our Pu-erh brand Jing Yu Tian Xiang, which we retail in China and abroad. We’ve also opened a new website:, on which we sell a wider range of Yunnan teas from our tea factory as well as from other farmers.”

What do you see is the main differences in selling tea based out of Europe and from China?

“Being based in China helps a lot with sourcing. As you know, building and nurturing relationships in the Middle Kingdom is extremely important, and it’s all the more convenient to be present all year-round.

Farmerleaf, Yu Bai processing tea

Yu Bai processing tea

Being based in a tea mountain in Yunnan is a great opportunity to understand the technicalities of tea production, and how the farmers make their choices in terms of agricultural practices. Some aspects of tea can only be understood by having a long term presence in a tea mountain.  Understanding the details of tea processing requires making dozens of trials, sharing tips with fellow tea producers and experimenting.

Being online-based, the distance with the tea consumers doesn’t affect the relationship, we exchange emails with our customers every day.  It is always great to receive feedback and questions. Our objective is to bring the tea lovers closer to the tea gardens. In 2017, we have decided to close the distance by running a Youtube channel. Some tea fellows even visit us in Jingmai, and it’s a pleasure to take them around our tea gardens.”

Farmerleaf Yunnan tea forest

What are some differences between Western tea enthusiast based tea traditions and the original Chinese traditions, or modern practices?

“The way tea is brewed in China varies widely, depending on the province and the interest of the tea drinkers. The most common way is to brew tea in a large glass, what is sometimes called “Grandpa-style” in the West.

Just like in the West, Gongfu brewing is reserved to the “hardcore” tea lovers and the professionals. It is more prevalent in Yunnan, Fujian and Guangdong, because these provinces have a long history of tea drinking. In the last decades, China has experienced a revival of the tea culture; this is a luxury few could afford in the past. Gongfu-brewing spreads along with high quality leaves, just like in the West.”

Your website mentions producing pu’er; do you also actually make any other types of teas?  Do you produce shou / shu? 

Farmerleaf 2016 Jing Mai sheng pu'er

“Yubai, my wife, has run a small tea factory in Jingmai since 2011. We now operate it together and produce white, oolong and Pu-erh tea. Our teas are hand-processed, which mean we cook the leaves in a wok instead of using a machine. That allows a finer control over tea quality and opens more possibilities. We’re developing a line of semi-oxidized tea that is unique in Jingmai, and we’re always trying to improve our Pu-erh tea processing. We do not produce Shu Pu-erh; the extra fermentation process involved requires special skills, big infrastructure and a lot of tea.

Usually, the large factory productions consist in batches of dozens of tons. Nowadays, it is possible to ferment the tea in micro-batches (as low as 100kg), we’re considering making such a production, but it still has to be outsourced. A lot of the fermented Pu-erh tea is made in Menghai , Southern Yunnan.”

Can you share a short summary of the character differences in teas within different pu’er producing areas?

“Pu-erh tea features a wide range of tasting profiles. That diversity is due to differences in aging, processing, and producing area. Just like the terroirs of wine, tea tastes different according to the genetics, location and management techniques of the tea gardens. It would take a whole book to detail the subtle variations between each mountain and their underlying factors.

Jingmai is famous in the world of tea for its orchid and honey fragrance. Some bitterness is present; astringency is more present than average. In young teas, the mouthfeel is generally light and sweet. The Jingmai profile is accessible to the beginners and makes a great introduction to the world of Pu-erh tea because it has a bit of everything. In comparison, Bulang tea is generally more aggressive, featuring more bitterness; Yiwu tea is soft and mellow, with a thick mouthfeel. Menkgu is renowned for its complex fragrance and sharp sweetness.  

However, there are many exceptions in each terroirs, and the result in the cup can be very different depending on the processing. In Jingmai, old-growth tea that received a high-temperature kill-green process will feature the typical high-pitched orchid fragrance, with fast-changing bitterness and a light body; while tea that went through a low temperature kill-green process will have a thicker body, more sweetness and a honey-like aroma. There’s a lot of possibilities in-between.

Some tea gardens are known to produce more bitter leaves, while others grow particularly fragrant leaves. It is indirectly influenced by the soil type, garden design and agricultural techniques. For example, tea that grows on sandy soil will receive less water and nutrients than tea grown on clay soil, and that will influence the physiology of the tea tree and therefore the taste of its leaves.”

What tea aspects indicate that a pu’er will age well, or what types of teas would it make more sense to not age?  One sometimes hears that in the original Chinese tea culture pu’er wasn’t intended to be aged to improve it; any thoughts on that?

“Good Huigan (sweet and fresh feeling in the throat) will be sustained through the years, and this is one of the main criteria on which pu-erh tea is evaluated.

Make sure the tea you aged doesn’t taste like green tea or isn’t too red when young. This degree of greenness depends on the way the kill-green process was done. An overly green or red pu-erh tea can be very enjoyable when young, and be disappointing after years of aging.

The big tea factory blends are generally intended to be aged, [and] they are not suitable for immediate drinking. Blends can be a safe choice for long term aging, even though they rarely contain high-quality material.

Bitterness tones down with age, but it doesn’t mean bitter teas will necessarily give a better tea once aged. For example, Yiwu tea generally has no bitterness, but it’s a sought after terroir for long term storage; this kind of tea can be unimpressive when young and turn into great sweet and complex teas after a couple of years of aging.

The Pu-erh tea culture is constantly changing; in its most current form, it is considered this tea can be enjoyed young, as it was consumed in Yunnan, and aged, as it was consumed in Guangdong. The Tibetan way of drinking it with Yak butter doesn’t seem to have spread much. In a pre-industrial context of smallholders, it was technically much easier to produce Pu-erh tea than other types of teas. When made in small quantity, the only piece of equipment required is a wok. Sun-drying was used to dry tea, just like it was used to dry fruits, corn or cabbage.

The tea culture has been shaped through the constraints of production and logistics. People like wet-stored tea in Guangdong because that is the way tea would turn out in those conditions. Some tea lovers in the West build “pumidors”, while I have never found one in China. It is beautiful to see the tea culture evolve as tea spreads throughout the world.”

What is the local (Yunnan) understanding of ideal and problematic pu’er storage conditions?  Is environment humidity the primary concern?

“In Yunnan, few people actively control humidity; they typically store the tea cakes in their bamboo wraps in cardboard boxes. When stored in large quantity, the air flow is somewhat limited, which is believed to preserve the fragrance of tea. Some tea professionals limit the air exchange further by wrapping the boxes with plastic sheets.  

2011 jingmai gushu leaves grande

This technique makes sense as long as the leaves are not vacuum sealed. The aging process does require oxygen to occur, but the air contained inside the box should be enough for decades. A minority advocates for a complete removal of oxygen, this slows down the oxidation process and the tea profile evolves in a very different way.

Aging is the result of enzyme activity, called “enzymatic browning” in the food industry, and the action of micro-organisms. The relative importance of each in the aging process depends on humidity. In wet environments, microorganisms take a large role in tea oxidation, while in dry environments, their action is negligible. This probably explains the difference in taste profile that we can observe between wet and dry-stored teas.”

What is the difference between using tea from just one plant to make tea versus mixing it?  Per input related to other tea types (eg. Dan Cong) the range of characteristics would be narrower; is this the same?

“Pu-erh tea Single tree productions have been popular for a couple of years. Since only one or a handful of trees are harvested, the result in the cup varies widely. Some can have a very good throat-feel; others can be bitter and astringent, or sweet and fragrant… A big part of the appeal is to have the picture of the big tree and the feeling of tasting something very old. Self-suggestion can go a long way to make your session enjoyable, even though such productions wouldn’t necessarily perform better than a standard “gushu” harvest in a blind tasting.

Such productions are valuable by their limited quantity; you can hardly get more than a kilogram of dry tea from a single ancient tree. They can feature traits that are unexpected in their area of production and tend to change less along the infusions than standard productions that involve thousands of trees.”

Farmerleaf tea tree

How much tea (leaf weight and dry weight) can an individual tea tree produce?

“It really depends on the size of the tree, frequency of harvest, varietal, nutrient availability, water, sunlight, pest and disease, pruning method… It can go anywhere between 500g and 5kg of fresh leaves per year (about 120g to 1.2kg of dry tea). Some trees are picked three times a year, while other are picked thirty times.”

What is your impression of how tea tree age affects pu’er quality or characteristics?

“The leaves harvested from ancient gardens tend to have a better Huigan (sweet and fresh feeling in the throat), they can feature more pronounced bitterness that turns quickly into sweetness. They have an oily mouth feel that can remind [one] of chicken soup. Their fragrance can be more complex than tea made from young plantations. Old-growth tea can generally be brewed more times than young plantations tea.

These differences can also be noticed when comparing young and older tea plantations. A lot of great tea comes from 50+ year-old tea plantations.

It’s important to keep in mind that the age of the trees is only one factor among others that makes good tea. The agricultural techniques and the location of the gardens (including altitude, soil, environment…) will have a large impact on the taste of tea. Some young plantations produce excellent tea, while some old tea gardens are not highly praised.”

To what extent can tea tree ages be identified?

“Following some heated debates on the internet, I have looked into the questions. Interestingly, I have found published scientific articles that discuss the age of specific trees. At best, the circumference of the trunks is measured, and this is only loosely correlated to the age of the tree. According to farmers and experts I interviewed, growth rate of the trunk varies widely, depending on soil fertility and genetics. In some cases, we can know the age of the tea gardens from historical records, but not the age of specific trees.

Farmerleaf Yunnan tea forest

The tree ring counting method does not seem to be used in the case of the tea trees.

Some vendors use the age of the trees as a selling point, but I would rather recommend using the size of the trees, which is easier to confirm.

Farmerleaf tea can be purchased here.