Types of Tea
To ensure the highest quality teas, the newest “two leaves and a bud” of tea plants are plucked by hand. This practice of fine plucking produces the best tasting tea but low yields – around two to three thousand leaves only translates into a pound of finished product.
This repeated picking of the young leaves and buds promotes new growth throughout the year. Depending upon the origin, bushes are plucked anywhere from three to twelve times a year. Plucking is often referred to as “flushes."
Transforming Leaves into Tea
The major types of tea including black, oolong, green and white all originate from the Camellia sinensis tea bush. The differences among the teas result only from the way the plucked leaves are processed.
Making black tea involves withering, rolling, oxidation and drying.
- Withering - Workers start picking early in the day and usually return to the processing factory around mid-day. These freshly harvested leaves are spread out on racks and left to wither for 14 to 24 hours. During this withering process, the leaves become soft and pliable loosing much of their water weight due to evaporation.
- Rolling - Next, from the racks leaves are fed into rolling machinery that break up the cellular structure and release the natural enzymes of the leaf. An elliptical motion created by large rollers exerts just enough pressure to roll and twist the leaf without causing heat damage. The resulting product is a green, pungent pile of twisted tea leaves.
- Oxidation - After the rolling, the leaves are transferred to a cool, humid location in the factory to begin the oxidation process, also commonly known as the fermentation process. Over the next two to three hours, the leaves release their enzymatic juices and oxidize upon exposure to air. A chemical reaction occurs whereby the mixing of polyphenols and pectin with oxygen and enzymes cause the leaves to turn black and also give black tea its characteristic flavor. Determining how long to oxidize the leaves involve considerable expertise and different styles of black tea demand varying time for fermentation.
- Drying - Upon the reaching the optimal oxidation level, the leaves are fired or dried to stop the fermentation. In essence, the drying seals in that particular tea’s characteristic flavor. Placed on large trays or on a conveyor belt, the tea travels through an oven chamber that halts oxidation and reduces the leaves water content to an ideal 2%.
As partially fermented teas, oolongs can be thought as teas sitting halfway between black and green tea.
- Withering - After plucking usually three to four leaves and a bud, oolongs like black teas undergo withering, but for a shorter period of time.
- Oxidation - Upon wilting, workers shake the leaves in bamboo baskets resulting in slight bruising and tearing of the leaf. As the leaf is exposed to air, and the enzymes react with the oxygen, it turns darker in color.
- Drying - The leaves are then fired to stop oxidation. Again, the duration of oxidation will depend upon the style of oolong. Traditional Chinese oolong is usually fermented up to a 10-15% level whereas a Taiwanese style oolong might be 70% oxidized. Interestingly enough, an oolong can exhibit more green or black tea characteristics depending upon the length of oxidation.
Green tea differs from black tea in that after plucking, fresh leaves are immediately steamed or pan-fired to stop any oxidation activity.
- Steaming or Pan-fired - In Japan, green tea is steamed, and in China, leaves are pan-fired in a wok or heated drum, both processes resulting in soft and pliable leaves. With the active enzymes locked inside, the leaf is ready for rolling.
- Rolling - Whether done by hand or with machines, rolling determines the unique size and shape of the green tea leaf. A tea growing location will dictate the style of rolled tea – resulting shapes include long thin leaves, tight balls, flat natural leaf and gently twisted green teas. The beauty of a tea and the taste profile is affected by the style and tradition of rolling.
- Drying - Finally, a gentle heating or firing afterwards allow the leaves to dry, preserving their fresh "green" characteristics. At the end of the process, the leave’s moisture content should be about four percent.
The least processed of all tea, the youngest new buds are freshly plucked, and then air or steamed dry.