First, let me say that the assessment of tea is primarily sensory. We start by looking at the colour and surface qualities, its friability, the size and consistency of leaves, evidence of bacterial action, we touch, inhale – and that’s before brewing!
We then take a sample, and if it’s old pressed tea, crumble it into a neutral vessel – white porcelain – add water of the temperature we judge appropriate for the particular tea, leave it for a short time and then pour into a glass sharing flask. Again, we inhale, pour into small cups and sip, allowing the liquor to roll back over the different surfaces of the tongue, noting what changes there are in the flavour, finally exhaling gently through the nose to judge the finish. We then inhale the remaining aroma in the empty sharing flask and the brewing vessel. Continued pourings allow us to judge the change in colour of the liquor, taste, and aroma. Finally, after pouring several times, we observe closely the 叶底 (ye di, last tea leaves).
In the case of the tea bricks at MAA, none of this is available to a distant observer, as I am in Shanghai, and moreover, for obvious reasons it would not be possible to brew any of these.
Figure 1: A pressed cake of dark tea, oval in shape. Tibet. Donated by Lady Caroline Schuster. MAA 1947.779.
Like the other tea bricks at MAA, this is a pressed cake of dark tea, destined for Tibet, where since the seventh century there has been a strong demand for tea without the ability on the Tibetan Plateau to grow it. Michael Freeman explains the beginnings of this trade, along what came to be known as the 茶马道 (Cha Ma Dao, Tea Horse Road) elsewhere in this blog. This kind of brick tea was typically produced in Hunan, Hubei, Sichuan, and Guangxi.
Dark tea occupies a special place among the several varieties of tea, which include green, white oolong, and so on. In Chinese it is 黑茶 (Hei Cha), which perhaps misleadingly translates literally to English as ‘black tea’. However, it is not what is in English referred to as black tea (we Chinese call this red tea because we refer to the colour of the liquor, not the dried leaves). While black tea is fully fermented and oxidised, dark tea continues to ferment slowly after processing, and this can continue for decades if the tea is allowed to last that long.
Colour, then, is an indicator of age, and the darker the older. There is some uncertainty here in the photographs I have available, as they vary in colour balance, and also in tone (that is, how dark). In the close view for example (#4), the colour seems lighter than its age of acquisition would suggest, and also yellowish-brown, which is a little puzzling.
Figure 2: Detail of the tea cake, showing the texture and the colour of the tea leaves. MAA 1947.779.
In the absence of colour targets, Michael has attempted a colour correction that aligns all of the photographs. If the colour of these is a true reflection of the specimen, then this dark tea’s quality is quite good, and may even be the best of the collection that I can see.
Figure 3: An attempted colour correction of images of the tea cake. MAA 1947.779.
Another main element for influencing dark tea’s quality is storage. Because dark tea is fermented by time, a good environment is important for it to ‘grow’, as with a baby. The essential condition is dryness and the avoidance of damp (a relative humidity of about 40-60%), but is also needs to ‘breathe’, so needs some air around it. The specimen appears to have been stored well.
If I were to guess the flavour profile from above, then I would hope for a silky texture to the liquor, a fragrance of old wood with sweetness arriving soon after the first taste and lasting long. And if we were lucky, then there would be light flowery notes.
