The diagram compares two methods of manufacturing black tea, namely the traditional loose tea process and the modern process used for tea bags.
Overall, both processes begin with the picking and withering of tea leaves and end with firing or drying. However, they differ mainly in the processing stage, where rolling is applied in the traditional method and cutting is used in the modern method.
At the initial stage, only buds and top leaves are harvested to ensure high quality. These are then spread on racks and exposed to air, which reduces their moisture content by about 60%. After withering, the procedures diverge. In the traditional method, the leaves are rolled until they are flat and broken, releasing enzymes. By contrast, the modern method cuts, tears, and curls the leaves, producing smaller granular pieces more quickly.
Following this, both methods involve oxidation or fermentation, where enzymes in the leaves react with air and change their colour to copper. Finally, the leaves are dried or fired in ovens or hot-air dryers. At this stage, 97% of the moisture is removed, while flavour and aroma are fully developed, resulting in the final black tea product.
In summary, despite sharing common starting and ending stages, the two methods differ in the way the leaves are processed, with the traditional method producing loose tea and the modern method creating smaller particles suitable for tea bags.