Sourcing Sun-dried Wild Red Tea
This Spring we sourced a wild red tea from Wuliang Shan. You can read about Wuliang Shan in our previous blog post.
Wuliang Shan has a significant amount of wild tea trees: non-clonal, genetically diverse varieties of Camellia Sinensis var. Assamica and var. Taliensis that are native to Yunnan. When sourcing raw puerh tea from Wuliang this year, we also wanted to use some wild tree material for a red tea, so we pre-ordered this material from the farmer. We also requested a sun-drying process for this tea. In this blog we explain why we requested wild tree material together with sun-drying.
Wild Trees and Cultivated Trees
Cultivated trees in Yunnan are dedicated clonal varietals planted on large plantations primarily for greater yields and production consistency. The red teas cultivated trees produce are often more brisk, with potential bitterness and astringency when pushed during brewing. Wild tree material are genetically diverse, and have a very different effect on tea. They often produce teas that last for more infusions with lower bitterness and astringency. Why? Ecological studies have shown that the leaves from wild trees in Yunnan are generally tougher, with more fibrous material and thicker mesophyll, epidermis and cuticle layers. This means they have abundant flavour precursors and are structurally more resistant to brewing with boiling water. Wild trees also grow in nutrient-rich forest soil, which can contribute to a more complex taste and aftertaste.
This is not to say that wild trees are inherently better for red tea than cultivated trees. There are plenty of excellent Yunnan red teas that are made exclusively from plantation trees. It's just that this year we wanted to source a Yunnan red tea with a specific profile: a mellower, 'introverted' character, lasting for many infusions, with a complex fruity aftertaste. For the type of red tea we wanted to source, we had to search for old wild tree material, and luckily we found some on Wuliang mountain. Once we found the material, we had to consider processing techniques. For this red tea profile, we needed sun-drying, as opposed to hot-air drying.
Sun-drying and Hot-air drying
Historically, Yunnan red teas have been sun-dried or dried with hot-air . Sun-drying is the older method, when ovens and drying machines were less available. Nowadays, a lot of Yunnan red tea is dried with hot-air, because it's faster, more suitable to factory-scale production, and yields a consistent product.
While there are plenty good hot-air dried red teas on the market, in our experience sun-drying is more suitable when the raw material is from older wild trees. As written above, wild trees can have greater aromatic complexity than plantation trees, so during processing, we want to preserve that aromatic complexity as much as possible. After the oxidation step, it seems the best way to preserve complexity is to allow slower oxidation and slight fermentation to continue during the drying process.
Because sun-drying takes place in the open air, oxidation of the tea polyphenols continues slowly during the drying process, similar to puerh tea drying. Native enzymes may also remain active under gentle sunlight, allowing a mild fermentation. In hot-air drying, the leaves are in a closed-air environment and exposed to a much higher temperature. This stops oxidation and effectively sterilises the leaves, halting all enzymatic activity. The end result is that a sun-dried red tea can be aged. The sun-drying process preserves some complex aromatic compounds, and the tea can develop fruity or hoppy fragrances due to fermentation as it ages. Some studies confirm that sun-dried tea retains higher levels of certain compounds, especially caffeine, catechins, and free amino acids.
Hot-air dried teas on the other hand tend to be at their best for about two years. They won't age or develop further because all enzymatic activity has been halted by the higher temperature. The more rigorous high temperature process can create pleasant chocolatey or malty notes, but this process is also more likely to result in a simpler flavour profile, with a more ephemeral aroma in the nose. With sun-dried tea, the fragrance can be more complex, and lasts longer in the throat.
Our desire to source a more interesting red tea with greater complexity and aftertaste is what lead us to choose wild tree material and a sun-drying process for our wild red tea this year. We hope you enjoy it.
References
Zhang, L., Chen, H., Chen, Z., et al. (2022). Changes in caffeine and catechin content in sun-dried black tea processed from Camellia sinensis var. assamica. Journal of Food Composition and Analysis, 109, 104453.
Li, R., et al. (2019). Effect of drying methods on the quality and chemical composition of black tea. Food Research International, 120, 30–37.
Zhang, Y., Zeng, Q., et al. (2016). Anatomical structure and leaf thickness of Camellia taliensis and cultivated C. sinensis var. assamica in Yunnan. Botanical Bulletin of Academia Sinica, 57(2), 127–138.