Green tea, Black tea, White tea, Oolong tea, Yellow tea and Fermented tea, all these types of tea are created from one plant; the Camellia Sinensis. The only difference is how the leaves are treated after they are picked and these processes help to reveal the plethora of colours and flavours that this versatile leaf can produce.
To begin with this is a chart which shows the simple steps each tea goes through:
Now let’s look at some of these steps in more detail.
Withering
All types of tea go through the process of withering, in simple terms it is leaving the leaves to evaporate moisture and dry out over a certain period of time. Sometimes this is done quite naturally in the sun, but in larger scale commercial production hot air is used to speed up the process.
How much withering is done will be different for every producer, but they all aim to have to have a consistent percentage loss for each batch. This is done by measuring the weight prior to withering and then again after a certain period of time, a constant percentage losses can then be carefully managed. The general aim is to make the leaves softer and more malleable so they are easier to process. Then they can move onto the next stages of production to create the various different types of tea.
Bruising
Bruising is exactly what is sounds like, the leaves are slightly damaged so that their cell walls break and oxygen can enter the leaf. This process is used to induce oxidation.
Oxidation
Oxidation is the process of enzymatic browning where oxygen reacts with the leaf cells to change the composition. This process is easily illustrated by cutting an apple in half and after a short period of time the core of the apple will go brown. This process adds hidden depths to the tea leaves and changes the appearance and flavour. We have a whole page devoted to oxidation, so click here if you want to learn more
Fixing
To halt the oxidation process heat of over 65 degrees is applied to the leaves, this is called “fixing” or “kill green”. This can be done by roasting, pan frying or steaming the leaves. This procedure essentially freezes their condition at that point, which is essential for making different types of tea, such as oolong teas where there is partial oxidation required and the leaves are then halted at their desired level of oxidation. In green tea this process is done immediately after withering in order to prevent oxidation occurring and in black teas after full oxidation it is often done together with the final stage of drying by using hot air to fix and dry the leaves at the same time.
Fermenting
This is the process where the green leaves are wrapped in cloth and left to ferment slowly over long periods of time, often years. The process can be sped up by “cooking” the leaves, so the same process happens over a shorter period of time. It is a form of slow oxidation where the leaves turn brown and their flavour and appearance changes.
Drying
This is the final step to remove the moisture from the leaves to stop them from spoiling or rotting. This usually done by blowing hot air over the leaves until the moisture level is under 5%. They are now ready to be packed up and sent to market and bought by you and me.
Infact why not look at our fully oxidised collection of quality black teas...