All teas, be they white, black, oolong, green, etc. all follow a similar manufacturing process with small variances:
- The newest leaves are picked (usually, the topmost bud and a few young leaves).
- The leaves are allowed to wither for a period up to 24 hours.
- The leaves are bruised, usually by being pressed through rollers, to activate the oxidizing enzymes under their surface.
- The bruised leaves are left to oxidize.
- The oxidization process is stopped by heating and drying to deactivate the enzymes.
The main difference between different types of tea is whether or not the leaves are withered and bruised, as well as the length of oxidization.
- White Tea is not withered or bruised and is immediately steamed to stop any oxidization before being dried. As such it is the least processed of all tea types. Additionally, many higher-grade white teas use only the curled leaf buds.
- Green Tea is generally not withered and is steamed to stop oxidization before being dried.
- Oolong Tea is allowed to oxidize anywhere from around 20% to 90% before it is dried.
- Black Tea is allowed to fully oxidize before it is tried.
- Pu Erh Tea can be prepared like Green or Black tea, but it is allowed many years to oxidize, and undergoes a second, microbial oxidization.
Cut, Tear & Curl Method
Simply bruising the leaves is the standard “orthodox” method of processing, and in the highest grade teas the bruising is done by hand. However, during the World War II era, another method known as “Cut, Tear & Curl” (CTC). Instead of rolling the leaves traditionally, the leaves are passed through a number of sharp, toothed cylinders that chop, tear and curl the leaves up into smaller pieces for oxidization. This process allowed for the transport of more tea in a smaller volume, as the resulting leaf size was very small (the perfect size of tea bags). This method has a number of advantages and disadvantages:
- The oxidization process takes a shorter period of time.
- Finished CTC leaves take up less volume per weight.
- The resulting tea takes a significantly shorter time to brew.
- CTC is more cost-effective.
- Loose CTC leaves go stale quicker than orthodox-prepared leaves unless hermetically sealed.
- It is easier to oversteep CTC leaves, resulting in strong, bitter tea.
- It is easier to cut CTC leaves with fillers, unnoticed.
- CTC leaves require packaging in Tea Bags to be brewed without difficulty, which leads to more waste paper and the leaching of paper flavors into the tea.