Gyokuro (refined green tea) (玉露)

Gyokuro is a kind of Japanese tea.

Summary
In terms of its manufacturing method, gyokuro is classified as a kind of sencha (green tea), but its cultivation process is characteristic. More specifically, gyokuro tea leaves, the raw materials of gyokuro, are cultivated under a cover for at least two weeks before being harvested. This process increases the quantity of amino acids, which result in the flavor of sencha, and decreases the quantity of catechins (so-called tannin), which cause astringency. Through this process, the tea leaves obtain a distinctive aroma (a particular odor gained through the covering process). This kind of cultivation method for gyokuro tea leaves is the same as for tencha (powdered green tea), and reportedly it was already practiced during the Azuchi-Momoyama period.

Origin
The name 'gyokuro' came from the trade name of a product sold by a tea manufacturer, Yamamotoyama. In 1835, the sixth owner of Yamamotoyama, Kahei (Tokuo) YAMAMOTO roasted tea leaves and rounded them into dew-like shapes at the house of the Kinoshita family located in Ogura, Uji City, which later became the original form of 'gyokuro' (which literally translates as "jade dew"). Today, tea leaves are roasted and processed into bar shapes. This current process was completed by another tea manufacturer, Toshiuemon TSUJI (Tsujitoshi) at the beginning of the Meiji period.

Features and varieties
Although gyokuro may be categorized as a high-class sencha produced in Japan, it is treated separately from ordinary sencha in fairs, etc. (refer to the articles on "sencha in the broad sense" and "sencha in the narrow sense"). For drinking, it is important to keep the temperature of hot water as low as around 60 degrees (or even 40 degrees, depending on the tea leaves) centigrade in order for the distinct flavor and aroma of gyokuro to leach out. Gyokuro is characterized by its sweetness, but if you brew it in water at a high temperature, the bitter ingredients of the tea leaves will also leach out.

As for types of tea plants, while most sencha and other Japanese teas are from the Yabukita variety, gyokuro is often made from special plant varieties with strong characteristics, such as Asahi, Yamakai, Okumidori and Saemidori.

While the name gyokuro itself isn't specifically defined pertaining to a particular use, there are many cases in which the tea leaves used in tea beverages called 'gyokuro-iri' (containing gyokuro) are similar to those of kabuse-cha (covered tea), which are not cultivated under trellises like real gyokuro but under a synthetic textile sheet that is put directly on the tea plants for fewer days than in the case of genuine gyokuro. The chief production area of gyokuro in Japan is Yame, Fukuoka Prefecture.

There, the twigs of tea plants aren't pruned and the burgeons are left to grow by themselves.

Trellises, which are installed with sufficient height from the top of each tea tree, are covered in rice straw.

Each burgeon and two nearby young leaves are plucked one by one by squeezing and drawing them through a hand.

The tea leaves produced as above in the Yame area are called 'Dento-hon-gyokuro' (traditional gyokuro for real) and are treated as distinct from other tea leaves. Gyokuro of high quality, exhibited at Zenkoku Cha Hinpyokai (the National Fair of Tea), are all Dento-hon-gyokuro.

Others
A name of a product similar to gyokuro is 'tama-ryokucha' (spherical green tea, also known as guricha) which is produced in Saga, Nagasaki and Kagoshima prefectures, however, its manufacturing process has no 'precise kneading' (straightening). Its leaves are somehow rounded and taste less bitter when brewed, having nothing to do with gyokuro.