What makes a tea black, green or oolong?

Canton Tea Club Week 67: Darjeeling First Flush ‘Himalayan Secret’

can this really be a black tea?

For those new to First Flush Darjeeling, this tea might come as a surprise. The dry leaves are dark green, with a few brown pieces and some white tips, in some ways similar to a green tea. The infused leaves are bright green with some reddish pieces, resembling an oolong. Finally, the liquor is golden yellow, and has a dry character reminiscent of a fine white wine. So how can this be a black tea?

It’s certainly unlike other black teas, even those produced later in the season in Darjeeling, and a world away from the dark and rich black teas of Assam and China. So what’s the story?

the First Flush in Darjeeling

Darjeeling is in North India, sandwiched between Nepal and Bhutan, in the lower slopes of the Himalayas. The climate here results in distinct seasonal growth patterns, much more so than any other tea growing area in the world, and these are reflected in the teas produced. During the cold of the winter, the bushes are completely dormant, and are pruned back hard. As the temperature and light levels start to increase during late February, new shoots start to appear on the pruned wood and eventually produce a covering of pale yellow-green on the bushes – this is the First Flush. Because different bush varieties and different parts of the tea garden come into flush at different times, tea is produced in very small batches and with distinct flavours.

This week’s Tea Club tea is a good example of this, as it was produced from 150 year old bushes in the ‘Heritage Section’ at Singell tea garden, and has a very distinctive, dry muscatel character. This character is specific to Darjeeling, and is one reason why it is known as “The Champagne of Teas”. If you allow a good First Flush Darjeeling to become cold, it has flavours reminiscent of a fine white wine. First Flush Darjeeling prepared in this way is perhaps the finest of all ice teas. I haven’t tried it with bubbles.

To be in a Darjeeling garden during the First Flush is a remarkable experience. The anticipation is palpable, as each morning brings new growth and picking decisions need to be made. It is not just the beginning of the season but also the peak of the season: what happens in this short period has a huge influence on the outcome of the whole year. It is a critical time for tea-makers, who must judge each small picking on its merits and process it to bring out the maximum flavour. The finest teas made in this period attract prices ten or twenty times higher than late season teas, and skilful handling and processing can make all the difference.

why is the tea so green?

The tea is made using the black tea process – pick, wither, roll, oxidise, bake – but it is affected by the unique characteristics of Darjeeling, particularly during the First Flush. The new leaves are very small and soft, and can be withered for much longer before rolling than the larger harder leaves produced later in the season. This long wither results in a lower moisture in the leaves. This reduced moisture, combined with low ambient temperatures, means that oxidation is slow and only partially completes before the baking stage.

The result is a tea that is pale in colour with a uniquely elegant flavour. It would be possible to make a blacker tea by withering less and using warm air during oxidation, but this would make a very different tea, which the world’s buyers are not looking for. Teas produced during the Second Flush have this darker colour and have a different balance of flavours, although still very recognisable as Darjeeling.

The best way of describing this classic First Flush Darjeeling is as a ‘partially oxidised black tea’. This is not the same thing as an oolong, which is made differently and has a unique flavour (please see the end of the blog).

how green can it get?

The association of First Flush with greenness in leaf and liquor has resulted in demand from some buyers for the greenest teas possible, assuming that this makes them the best. This can be done by over-withering and under-oxidizing to an extreme, producing tea that is very green in appearance, but not a green tea (see later). The taste is harsh and unpleasant – it reminds me of chewing on a rubber band. This has not affected demand, and some gardens now specialise in making tea of this type. Each year there is a race to have the first new season teas on sale in teashops in Germany and Japan, and these two factors have combined to deliver some truly awful (in my opinion) First Flush Darjeelings on sale in the most prestigious outlets. There must be some very disappointed customers out there who wonder what all the fuss is about.

what is the best tea to buy?

Many people look for the first invoice of the season – usually called DJ1 – and this is often promoted by sellers. The first teas of the season can be the best, but more often the teas produced during the second week or so have much more elegance and complexity. The best teas are produced from older small-leaved China v bushes, when a tea maker is free to optimise the process rather than force it for specific markets or customers. Such teas are sometimes referred to as ‘China variety’ or ‘Vintage’. This week’s tea could be described using both terms, and I think it is a particularly good example of an elegant and well-made First Flush Darjeeling.

what makes a tea Black, Green or Oolong?

This is often answered by referring to the level of oxidation, e.g. “green teas non-oxidised, black teas fully oxidised, oolong teas somewhere in between”. Although this is a convenient shorthand, it is not entirely accurate – as we have seen with this week’s Tea Club tea.

It is better, but more complicated, to define teas by their entire method of processing. Although it is technically possible to make any type of tea from the same leaves, in practice specific bush varieties are selected for each particular type. Oxidation is an important stage, but is managed as part of the process rather than automatically determining the outcome. I would prefer to define the tea types as follows:

Green Tea: withered leaves are heated using a hot surface or by steam until the enzymes in the cells are denatured (killed). Once this has happened, the leaves can be rolled, twisted or shaped without any oxidation taking place. The final process is baking or charcoal roasting.

Black Tea: withered leaves are rolled or crushed to break the cell walls, allowing the polyphenols and enzymes to come together and react with the oxygen in the air. This process changes the colour from green to brown, and creates the familiar black tea flavours. The process is stopped by baking. In some cases the final baking takes place before oxidation is complete, resulting in partially-oxidised black tea.

Oolong Tea: withered leaves are tumbled or rolled to allow a degree of cell rupture and a gradual process of oxidation. When the leaves are sufficiently oxidised (this depends on the type of oolong being produced) the leaves are baked to fully kill the enzyme before a final rolling or twisting stage. The final process is baking or charcoal roasting, which can be repeated.

does it matter?

Well obviously it does to me, but what about those of us who aren’t tea geeks? I would make the case not because of technical fussiness or semantics, but because of the artistry of the tea makers. They select particular varieties and use specific techniques to craft individual teas of character and beauty. For example, to describe an oolong as a partially oxidised (black) tea simply doesn’t do any justice to the traditions and skills involved.

Let’s return to this week’s tea, the Singell First Flush ‘Himalayan Secret’. The tea maker has used specific techniques to bring out the flavour of the young leaves, and to do this he has used the black tea process with a partial oxidation. The result is dry, crisp, intense and elegant.

It’s very, very good. And it’s nothing at all like an oolong.