Not just when making wine, whisky or even bread. The process of fermenting in tea is similar but without the addition of any additional bacteria or yeast. All of the microorganisms that are needed are present in the juices of the tea leaves.
When the leaves are rolled (as we saw in the last blog – Speciality Tea Part 2 – Drying and Rolling) this gentle action of crashing the leaves releases the juices and this is all is needed to start the process of fermenting tea.
The Tea Master/Estate Manager will determine how many times the leaves are rolled. This would be to achieve grades of tea leaves. From the larger tea leaves (OP) to broken leaves (BOP) to dust and fannings (commonly used in tea bags by the larger tea companies).
Once the required size of the tea leaves have been achieved by rolling, the fermentation process which started in the rollers is allowed to continue when the leaves are laid out on beds. Fermenting beds are set out by leaf grades. These beds are in temperature controlled rooms that are cool and humid. This will take up to 3 hours.
The Tea Master will determine and control the temperature, humidity and length of fermentation. S/he will be looking for tea at its optimum and will halt this process when they think they have achieved that result.
When the tea leaves go through the rollers, they are a dark green and when they are laid out to ferment are a coppery hue. As the tea ferments the colour will darken and become a rich brown.
Naturally occurring chemicals; theaflavins and thearubigins develop during the oxidisation process. This gives tea its familiar flavour and aroma.
At the optimal time, the tea leaves are removed and conveyed to the drying table
To arrest the oxidation process when it’s reached its height, the tea is moved into dryers. The dryers have hot air blowing through them which dries the tea and reduces the moisture content even more.
By the end of the process, the tea leaves will only have some 2-3% moisture left in them.
There are number of ways of drying tea leaves, as in this factory in Sri Lanka, the tea is left to air dry for a while before being moved to the dryers;
The dryers will also sort the tea leaves by grade and deliver it the packing area of the factory for the next stage of its journey.
To read Parts 1 and 2 – https://missteasmith.com/blog/