Good tea quality for a green oolong has to have the following features:
- The appearance of dry tea: The appearance should be a tight knot, a bright green tea color, clean and not doped.
- The color of liquor: Tea liquor is yellow, clear and bright with oily shininess.
- Fragrance: The aroma, pure and floral, arises directly from the tea leaves. The elegant fragrance comes out through the nose while breathing out right after sipping the tea liquor. It tastes sweet, mellow, smooth and full of energy. The most important is its aftertaste (Hui Gan).
Green oolong tea is the late creation of tea category. The tea is produced with the most complicated processing conducted with the most sophisticated technology and the most difficulties. There are some common defects summarized as 10 don'ts for green oolong teas, described as follows:
- Stale smell: Caused during preservation process, due to a.) auto-oxidation of catechins b.) cleavage of chlorophyll c.) denitrification of amino acid d.) moisture absorption e.) tea oil oxidized and producing oil taste. The tea quality with stale smell is marked as a serious defect.
- Astringent taste: As for the green oolong tea, the formation of astringent taste is generally caused by "improper indoor withering and tossing". The emphasis during the producing process is the appropriate degree of fermentation. Less fermentation will cause light astringent taste while improper fermentation causes thick astringent taste. Improper tossing also causes tea tissue damaged which results in the water unable to evaporate. Therefore, it's easy to form grassy astringent taste in the tea quality.
- Grassy taste: A. Cultivation and management: too much nitrogen fertilizer applied will result in dark green leaves, lack of flavor, and grassy. Or picking too old tea leaves will lead to the formation of grassy taste. B. In the tea producing environment: during the tea withering process, with low room temperature and high humidity, water is not able to evaporate naturally, thus tea is unable to carry out the fermentation also causes the grassy smell. C. In the process of production: picking too tender leaves or improper picking with early morning dew, it's easy to lead to leaf tissue damaged. Water evaporation is not smooth (called water accumulation). The color of finished product shows dark, smells the grassy odor and is hard to consume. In addition, not enough frying process also causes the formation of grassy taste.
- The burnt smell from frying process: The purpose of frying process is to make enzyme inactive, to stop the fermentation, to reduce moisture and to boost leaves becoming soft so as to facilitate the rolling operation afterward. If the temperature and time control is improper, the burnt smell occurs, the taste loses freshness and smoothness of green oolong teas.
- The burnt smell from drying process: In the traditional hot air drying method, whether it is gas or oil burning as a heat source, the temperature used the most is 85 ℃ ~ 100 ℃. In order to dry moderately, the second time of drying is conducted. The high temperature will destroy the flavor and should be avoided.
- Cooked smell: Elegant fragrance and delicate taste are important quality characteristics for the green oolong teas. If the baking temperature and time are not in proper control, the tea smells cooked.
- Weak taste: The raw and old leaves are picked as material. The fermentation and rolling process are insufficient. The preservation is not adequate or too long. These factors lead to the weak taste and lose the thick and mellow flavor of the camellia sinensis.
- Smothered taste: If not timely to exclude water vapor in the frying process, or not timely to unblock in the rolling process, the tea tastes smothered and unclear, losing the freshness of tea.
- Bad odor: The smells that tea should not have such as smoke, musty, oily, sour, earthy, sun and other bad smells.
- Mixed smell: Tea is a material with the tissue of porous structure. It is easy to absorb odors and moisture. If the tea absorbed with other odors, it becomes turbid and unclear.
Original author: G. R. Chen/Director of TRES
Translated and edited by Adm./Fong Mong Tea Corp, all rights reserved.Origin from: http://www.tres.gov.tw/view.php?catid=1681