The different methods of black tea fermentation

Black tea is not a variety of tea. All teas come from the same shrub, the tea plant (Camellia sinensis). Their name is due to a single phenomenon: oxidation. Certainly, we hear a lot about fermentation, but the term is incorrect. Black tea is therefore an oxidized tea thanks to a very specific process.

1. Black tea oxidation (or fermentation)
2. Tea naming

Black tea oxidation (or fermentation)

Black tea production knows two methods. The orthodox process, which takes its time and requires several steps to obtain a quality black tea. It is found a lot in China and India. Better in taste, but also for health, these are the teas you should favor.
The CTC method, on the other hand, consists of optimizing production. This can give black teas of varying quality. So be careful about the origin and prefer teas from known provinces: Yunnan, Keemun, etc.

Black tea oxidation: classic method

The traditional process for making black tea takes place in several stages (just like for other teas).

Withering

Right after harvesting, the tea leaves are dried, until their moisture content is reduced by half. For this, grids are used on which the leaves are spread, and air is blown at a temperature of 25 degrees. The leaves are of course turned and stirred regularly. This step lasts about 24 hours.

Rolling of tea leaves

Here, the tea leaves are "rolled" in order to extract the essential oils. While this operation is now performed by a machine, some great teas are still rolled by hand. These are very high-quality teas.

Oxidation

This is the most important and controlled step, from withering to rolling. Oxidation occurs when polyphenols come into contact with air. It's the same phenomenon as with apples or avocados. These polyphenols are usually protected by vacuoles, except when there is a "break". Chlorophyll also undergoes a transformation, changing the pigmentation of the tea leaves. The more a tea is oxidized, the blacker it will be.

Fixing the oxidation

The last step of the process, fixing consists of stopping the oxidation. The method is simple. The tea leaves are exposed to a heat source, for a longer or shorter time. Once the oxidation is stopped, the black tea is packaged and ready to be consumed as a beverage.

CTC

Crush-Tear-Curl, literally Crushing-Tearing-Rolling, is a method that aims to reduce production time. The black tea concerned by this manufacturing method is generally of lesser quality than that which has received classic treatment. It is often intended for tea bags. The cost of this method is much lower and allows the use of damaged tea leaves.

Tea naming

In China, black tea is called red tea, because of the copper color the water takes during infusion. This can lead to confusion with rooibos which comes from another plant and is therefore not a tea, but an infusion.
They may also call it fermented tea, which is a mistake. Indeed, black, white or green teas have the same preparation. It's the oxidation steps and their duration that change depending on what you want to obtain. Only yellow tea is fermented. For example, Pu-Erh is a yellow tea with a taste that changes over time.
Another case of confusion is Oolong. Despite its color after infusion (the Chinese also call it raven tea), it is not a black tea. Its oxidation is between green tea and black tea. It is also less rich in theine.
Black tea is mainly consumed in the West. Its cultivation is practiced in many countries, however, it is mainly intended for import. The English are indeed those who drink the most.