I’m often asked about what makes some young puerh teas so ‘green’ in flavour and in colour, while others don’t have so much of this greenness to them.
The big difference is the level of oxidation of the leaves prior to the kill-green stage. After the leaves are picked, they are spread out and left to wither (ideally for around 4-6 hours but this is dependent on the weather and the water content of the leaves) to soften the leaves so they don’t break during the kill green process.
Extending this period of time brings out more floral & fruit characteristics in the flavour and aroma of the tea, whilst toning down the greenness of the tea. Some producers do this on purpose to achieve these characteristics. Personally, I prefer this limited time period, to produce a young puerh that is clean, bright and fresh, while keeping as much power and strength in the tea as possible.
There seems a tendency among some western drinkers of puerh, in their writings on the internet, to attribute the oxidisation of the leaves to ‘tweaking’ or some such nefarious processing techniques on the part of the producers to make their young puerh more widely palatable. While some producers do purposefully oxidise their teas a little more, more often than being a conscious decision, I feel generally the oxidation of the leaves shown in many young puerh teas is an accidental side effect of careless processing.
When the leaves are being picked, perhaps the farmer is stuffing too many into the bag he’s carrying or emptying too many bagfuls into a larger sack. The leaves at the bottom will become bruised and begin to oxidise too much & too early. Perhaps the farmer is careless with slinging this large sack of fresh leaves onto the back of his pickup truck or strapping it onto the back of his motorbike. Perhaps the place he is doing the kill green process is too far away from the trees where the leaves are picked, or perhaps he’s tired, has too many leaves to process and doesn’t get around to the kill-green stage until the next day.
In the kill green stage the intention is to halt the oxidation of the leaves completely. The difficult part is to use enough heat and time to heat the leaf sufficiently to penetrate the thicker parts of the leaf and stem, while not burning the thinner edges of the leaf. This is why in many teas one can find leaves that are slightly singed around the edges & the tea liquid will have excessive little black specks in the bottom of the tea soup. On the other end of the scale, perhaps the leaves will not have been heated enough, or not thoroughly enough and there’ll be reddened stems and/or leaves.
Some of these traits are normal in a hand processed tea, but the percentage of leaves with these characteristics should be limited and definitely shouldn’t be excessive, lending to the defining characteristics of the flavour. The leaves should also be more or less completely green, a sign that the kill-green process has been thorough and a few slight specks of black in the bottom of one’s cup lends some confidence that the tea has been hand processed rather than having the kill-green stage done by machine.
The accidental oxidation of the leaves through careless processing is so easy and so common that I feel this is much more likely in many cases than an intentional decision to oxidise the tea to a higher degree.
There are other variables too – the age of the tea is one. The greenness is the first characteristic to go as the tea ages. So if a puerh tea is pressed with maocha that’s a few seasons/years old, it won’t taste so fresh and green. Recently I tried a cake, purported to be from this spring, but was quite probably not. The fresh greenness had subsided and there was a characteristic slight honey-sweet flavour along with a very slight storage flavour.
Detecting these flavour profiles is really a matter of experience. There’s no substitute for attentively drinking a lot of tea, from different producers and of different styles. More and more these aspects will become obvious and with some pointers in the right direction and logical reasoning, one will naturally be able to discern more and more varied characteristics.