Normally made as strips or granular shapes, black tea is renowned for its red color brew. Large leaf species and medium leaf species are best suited for making black tea. Forming both shapes requires the fresh tea leaves to be in the same state. The leaves used must be tender, thick and covered with plenty pekoe so it can remain fresh for a long time. The process of black tea production is five stepped; withering, rolling, fermentation, drying and sifting.
Withering is evenly removing water from the fresh tea leaves. Withering is very important because if not, in the rolling process, they are easily broken and hard to be shaped into strips. Withering includes three ways as Sun Withering, Indoor Withering, and Withering using a Trough. Though dependent on weather, sun withering is the fastest, and easiest to apply. When the weather doesn’t allow, indoor withering is used, and it leaves good quality leaves. The Withering Trough is a hot air blasting machine, a method that solves the weather problems.
The significance of rolling is on the forming of Black Tea’s quality and appearance, especially strip-shaped tea. Rolling will break the leaf cell and can push out cell sap, promoting the enzymatic oxidization of polyphenols. This is what brings about Black Tea’s aroma, color and flavor. Rolling determines the strip shape of Black Tea, the leaves shrink during rolling, and these are then twisted into tight thin strips. As the cell sap is squeezed out to the surface, dry tea leaves will become a dark glossy color. Soluble substances rolled in leaves are easier to be dissolved, increasing the density of tea liquid.
Fermentation of black tea is a series of chemical changes prompted by enzymes during the making process. It mainly refers to the oxidization of polyphenols process. Fermentation is the key process determining Black Tea’s quality. It promotes the oxidization of polyphenol in the tea leaf with the help of enzymes; meanwhile other chemical substance will change, altering the leaves from a green to a red color. This is where the unique aroma and flavor of Black Tea comes from.
When the right amount of aeration (fermentation) has occurred, the leaf is dried in a desiccator or ‘firing chamber’ at 99-104˚C (210-220˚F) to prevent further chemical changes. This shrinks and darkens the leaf, resulting in the product known as Black Tea. This completes the actual manufacture.
The size of the leaf particles in your teapot bears no relation to quality per se, but it does affect the color and strength of the brew. Manufactured tea is graded by leaf size using a mechanical sifter. Leaf grades contain the largest pieces; broken grades are successively smaller, while the smallest grades of all are known as Dust. The larger grades tend to command higher auction prices.