Loose Leaf Oolong Tea: The Process Of Fermentation

by Elena Popec 24. September 2010 12:39

Oolong or Wu Long means "Black Dragon". Oolongs are half-fermented (or semi-oxidized) teas that are in the specialty tea family. Half-fermented because the processing of Oolong tea requires only a partial fermentation (oxidation) of the leaves. Oolongs occupy an intermediate position between non-fermented green teas and fully fermented black teas and are the most diverse and interesting loose leaf teas. Oolongs can have varying degrees of oxidation that ranges somewhere between 10-35% in classic Chinese Oolongs to 60-70% in classic Taiwanese (Formosa) Oolongs. Oolong specialty tea is often made from mature leaves, collected from older tea trees.

Processing Oolong is considered the art of tea, where the character of tea is created. Tea masters participate in Oolong tea processing competitions to demonstrate their professional skills at this fine art.

Let’s take a look at Oolong manufacturing process.

There are no standard recipes on how to manufacture oolong tea; it is up to the discretion of each tea garden or tea master to decide on processing and the level of oxidation.
 
Immediately after gathering, the tea leaves are spread in a thin layer on special bamboo mats under direct sunlight for withering that will let most of water evaporate. The withering process time varies depending on the ambient temperature.
 
The next step of processing is very peculiar, withered leaves are placed in a large bamboo basket and put in a shady area. Approximately every hour, the tea leaves are shacked and gently tumbled in order to bruise the edges of the leaves to start an oxidation, at the same time avoiding breaking or crushing them. This procedure has to be done several times, until following effect will be reached: bruised up edges of the leaves due to the fermentation become brown blush (like 'rusty'), while veins and parts of the leaves should remain green.

Once the desired level of fermentation is reached, the oxidation process should be stopped immediately. This is achieved through the heat drying phase of raw materials in scorching air called "panning". The pan roasting of the leaves requires extensive experience in Oolong tea processing.

Most Oolongs are dried in two stages: first is partially, primary drying and rolling of tea leaves, then a final finish drying. Some highly fermented Oolongs undergo an additional stage of wetting and softening.

The partially drying process is carried out manually. This stage is necessary to stop the fermentation. Partially drying can be done in 2-4 steps, when the raw material is taken out of the oven, quickly cooled, then rolled. Then again dried in the oven, rapidly cooled, then rolled again, and so on. Afterwards, the leaves go through a final drying phase, ending oxidation and often followed by baking (roasting). Several kinds of Oolong are not rolled just dried after panning. With such a "multistage" technology, taste and degree of fermentation of Oolongs differentiate. Although, manufacturing Oolong is very intensive and meticulous process, unique aroma and flavor profile of this specialty tea makes this tea worth the trouble.

Good quality Oolongs are only loose leaf teas, not tea bags!

The most widely known and actively exported Oolongs are Chinese (Fujian and Yunnan) and Taiwanese (Formosa). Among the most well-known are Formosa Oolongs. Grown and manufactured in Taiwan, named after the province in which grown, these teas are considered the best in quality and affordability among Oolong the loose leaf tea family. Taiwanese Oolongs are often called "Champagne of Teas". Typically Taiwanese Oolongs are specifically labeled that indicates the quality of tea:

1. Fanciest or Extra Fancy
2. Fancy
3. Extra Choice or Extra Fine
4. Fine
5. Fully Superior
6. Superior
7. Good
8. Standard

Chinese Oolongs are famous for the fact that are used in a Chinese traditional procedure named Gongfu Cha and withstand up to 7 steepings.

Brewing Oolong is a very delicate process because it strongly depends on the type of oolong, more precisely, the degree of its fermentation. A lightly fermented Oolong is closest to the brewing of green tea with 190-195 degrees water and the brewing time 1-3 minutes. More fermented Oolong (such as Formosa) is brewing a little longer 4-5 min in hotter water 203-212. After brewing a quality Oolong has pronounced specific characteristics that cannot be mixed with any other kinds of tea.

 The best quality Oolongs expresses a strong and rich floral aroma and a remarkable peachy flavor with a honey-sweet aftertaste. Oolongs that closer in oxidation to black teas, have a nutty, toasted flavor. Color of brew is very diverse: from light yellow with green notes (like green tea) to a dark red. Oolong specialty teas contribute 2% of tea consumption of all the teas all over the world.

Enjoy a great cup of Oolong, happy drinking!

Tea: The Essence Of The Fragrance

by Steven Popec 29. April 2010 20:37

The fragrance of tea depends on the essential oils and tar substances that are contained in plants. Essential oils are complex mixture of substances that belong to the most diverse class of compounds which are soluble in organic solvents and possessing the ability to escape from water vapor. Overall the total content of essential oil is minimal; it is determined by only hundredths of a percent. For example, aromatic black tea contains about 0.02% of oil. Pure essential oil of fresh tea leaf is a green color with a strong fragrance of fresh greens. In the technological processing of tea leaf occurs the formation of a new aromatic substances that contribute to the specific flavor of the finished product. Thus, the composition of essential oil of green plants is different from the finished black tea. The substances that make up the oils can be divided into 4 main classes of compounds: acids, carbonyl compounds, alcohols and phenols. These volatile compounds found in tea are trace amounts - 0.01% of dry matter, but their role in the establishment of the tea flavor is tremendous. 
 
Some parts of the plant contain different amounts of volatile compounds, which, in turn, differ in their compositions. The maximum concentration of essential oil found in the tender stems and leaves. The top leaf with the growing bud and two next leaves are equivalent to the content of essential oil. Further down the stem, as general coarsening occurs, oil content decreases. Which explains why the top three leaves are the most vaulable for high quality tea. 
 
In the formation of the aroma of tea, the main role is played by aromatic aldehydes (Organic compound that has OH-group in its structure. They are used in organic synthesis as fragrances). In the composition of essential tea oils are vanilla, lavender, cinnamon aldehydes, etc. During the processing of tea leaves into black tea, the various fractions of volatile compounds undergo significant changes. The total content of these compounds increases most radically in the early stages of rolling. In the process of withering the relative content of components with higher boiling point reduces and low-boiling point, on the contrary, increases. 
 
Along with essential oils important role in creating a tea aroma played by various resinous substances - carriers of flavor. They are in a close chemical relation with essential oils and are a complex mixture of different classes of organic compounds. 
 
The content of tarry substances in tea leaves ranges on average from 3% to 6%. These substances are separated by several fractions, the most valuable of which is a neutral faction. It has a pleasant sweet floral aroma. In the process of technological treatment , the amount of this fraction in tea leaves increases by 40%. 
 
During the processing of tea leaves, the content of resinous substances decreases, indicating the result of oxidation. I.e. ratio: fresh leaves – 3.48%, withered leaves – 3.27%, after two hours of curling – 2.92%, semi-finished product – 2.35%. 
 
Through fragrance of tea, all the deficiencies that have arisen as a result of violations of technological regimens or improper storage of products, can easily be found. Disadvantages may include: acidity, mustiness, smell of the green, smoke and other uncharacteristic for tea scents. Most difficult to improve defect is acidity, which results in a violation of the fermentation process. Since in the processing of tea leaves, especially during the fermentation, occurs a reduction of Tannin. Therefore, the tea produced in violation of this process turns out with a bitter flavor and pale color of infusion. The cause of the smell of greenery is an infringement of withering, rolling, and fermentation. Such a tea has a mild flavor that the brew is a greenish color in the cup with a greenish ring on the surface and instead of the characteristic astringent taste; this product has a bitter taste. If there is excessive moisture in semi-finished product (more than 7.5%) tea is aging much faster. For extended storage. it gets the smell of dampness and can come in unsuitable conditions for consumption. 
 
In addition, it is worth noting that different varieties of tea, as well as different ways of brewing, have an imprint on the final quality of the drink

Copyright 2010 © ESP Emporium.com. All rights reserved.

Twitter

The remote server returned an error: (404) Not Found.