Gyokuro

Though it is categorised as a type of sencha according to production methods, gyokuro cultivation differs from other sencha teas. Gyokuro tea leaves are shielded from the sun before being harvested. The period can vary from twenty to thirty days. Three weeks / twenty days is a standard length of time for a tea to be considered gyokuro proper. The shading causes both the amino acid L-theanine and the alkaloid caffeine in the tea leaves to increase, and the catechins and tannins to decrease, which yields significant differences from the flavour of sencha. The shading causes the plant to stop converting theanine into catechins to protect itself from UV light. It also produces a calming effect which balances out the high caffeine content of gyokuro. Studies on L-theanine indicate that it may also help reduce stress and anxiety and may have neuroprotective effects. The length and type of shading or covering (kabuse) will affect the taste of the gyokuro tea. Shading may be done with a scaffolding built over the tea field or by covering the plants directly with the shading material (jikagise). These parts have a high concentration of theanine due to their lower photosynthetic activity compared to the leaves, have less caffeine, and also contain different aromatic and flavourful compounds, making their flavour distinct from standard gyokuro. A rough unprocessed mix of gyokuro leaves, broken particles, stalks and stems, is also sold separately as unprocessed tea / unrefined tea (aracha). These rougher types of gyokuro tend to be less expensive than standard leaf only gyokuro. ==Brewing==

teapot Brewing gyokuro is generally done with lower temperature water (between 40 and 70 celsius; 104 to 158 fahrenheit depending on the leaf and personal preference). The traditional Japanese method of brewing gyokuro uses a high water to leaf ratio, usually around 5 grams of leaves for 150 millilitres of water. Since the leaves are tightly rolled and need time to open, the infusion time is usually longer than other green teas (2 minutes). After the leaves have opened, the same gyokuro can then be re-infused three or four more times for 20–30 seconds. In the practice of Senchadō (the way of sencha), many schools use a "two-step brewing" method. First, low-temperature water, cooled by initially pouring it into a separate cooling vessel, is used to extract sweetness. Then, high-temperature water is used to extract bitterness. There are also schools that add a "three-step brewing" method, which use water of intermediate temperature for the second infusion to extract astringency. However, due to the increased time required for each session and the fact that the components may be almost fully extracted by the second infusion for some tea leaves, the "two-step brewing" method is more prevalent at large tea gatherings. Small teapots such as koburi or houhin (small teapots without a handle) are often used, and the tea bowls are also smaller compared to those used for sencha. == Regions and market ==

More than 40% of gyokuro is produced in Yame (Fukuoka Prefecture), and in the national tea jury in August 2007, Yamecha (Yame tea) held all the ranking positions from first to 26th as the best gyokuro. A high amount of Ujicha gyokuro is also produced around Uji, in the Kyoto prefecture (140 tons in 2008). In 2008, the production volume of gyokuro in Mie Prefecture increased more than 40 times compared to the previous year (132 tons in 2008, 3 tons in 2007). The process was completed by another manufacturer at the start of the Meiji period. ==See also==