Gyokuro offers a thick umami sensation like soup, with an intense seaweed-like flavor. This 100% authentic natural flavor comes from a special tea growing method.
The characteristics of Gyokuro are entirely different from Sencha. Gyokuro should not be seen as a superior version of Sencha; it is a completely different category of Japanese green tea.
Distinctive Characteristics of Gyokuro
Gyokuro tea leaves are very deep green in color, and its flavor resembles seaweed, with a mellow and sweet taste. The same cultivar used to produce Sencha can also be used for Gyokuro. The secret lies in the special growing method: about 20–30 days before plucking, the entire tea garden is covered with sheets, shielding the tea trees from direct sunlight. This lack of sunlight triggers physiological and chemical changes in the tea leaves, producing the unique flavor substances of Gyokuro, which are extremely rich in minerals. We select our Gyokuro from Okabe Town in Shizuoka Prefecture, known for its clean air and pure alpine water. We call it Asahina Gyokuro.
Hon Gyokuro: The Genuine Gyokuro
The Gyokuro we selected is Hon Gyokuro, meaning "genuine" or "authentic" in Japanese. The name Hon Gyokuro is reserved for tea produced from gardens covered with straw, a traditional method that is rarely practiced today. Most modern Gyokuro gardens are covered with black sheets called Kanreisha.
Three Major Categories of Covered Tea
- Tea trees covered directly with sheets, with no headspace between the trees and the sheet. This type of tea is called Kabuse Cha.
- A framework is built around the tea garden and covered with black sheets. This is the most common type of modern Gyokuro garden. The temperature inside tends to be very high, causing the tea to grow faster and be plucked earlier in the season.
- A framework is built around the tea garden with much less headspace between the tea leaves and the covering. The tea leaves almost touch the ceiling, and the garden is covered with straw. This is called Hon Gyokuro. The temperature inside is relatively lower, and plucking occurs much later. Our Asahina Gyokuro is produced in this rare style.
The Unique Flavor of Hon Gyokuro
The taste and flavor of Hon Gyokuro are remarkably different from ordinary Gyokuro. Hon Gyokuro provides a strong aftertaste, with a long-lasting sweetness that lingers in the throat. Ordinary Gyokuro emphasizes umami contributed by amino acid content, but without a deep aftertaste it can taste flat. Hon Gyokuro combines a long-lasting flavor with umami. This difference is due to the straw covering, which is rich in minerals—when it rains, water soaking through the straw supplies additional minerals to the soil, drastically improving the quality of Hon Gyokuro.
Fresh Straw for Quality Hon Gyokuro
For our Hon Gyokuro, fresh straw is crucial. According to Mr. Omura, the owner of the Hon Gyokuro tea garden, fresh straw is rich in minerals and tastes sweet, whereas recycled straw from previous years does not retain sufficient minerals. To ensure a fresh supply, Mr. Omura also owns a large rice field, and his wife produces the straw sheets. This labor-intensive process is one reason why most tea gardens have switched to using black plastic sheets.
Challenges in Producing Hon Gyokuro
Most farmers choose to produce ordinary Gyokuro because it commands a high price in Japan, especially when plucked early in the season. Hon Gyokuro, on the other hand, grows more slowly to enhance its quality and is plucked later. This market preference—driven by a misunderstanding that umami is the primary quality index—makes it difficult for farmers to invest the time and effort required for Hon Gyokuro. As a result, Hon Gyokuro is rarely available on the market and is usually sold directly to specialty tea shops that appreciate its value.
Ordinary Gyokuro garden covered with black sheets
Hon Gyokuro garden covered with straw
1. History and Culture
Okabe Town is located northwest of Shizuoka City. The alpine Asahina River runs through the town, and both sides are surrounded by steep mountains. The Asahina District, located north of Okabe Town, has hilly land and a typical mountain climate, making it suitable for producing high-quality tea. Tea has been produced here since the Muromachi era, and Gyokuro was invented in 1835. Originally, Gyokuro tea gardens were covered with bundles of rice straw. Today, Asahina (Shizuoka), Uji (Kyoto), and Yame (Fukuoka) are the 3 major Gyokuro producing areas in Japan.
2. Production Area
About 30 days before plucking, Gyokuro tea gardens are covered. Initially, the shading rate is 65–70%, increasing to 97–98% as covering progresses. Theanine, an amino acid that contributes to the umami and sweet taste in green tea, is produced in the roots and transferred to the stems and leaves. When exposed to sufficient sunlight, theanine is degraded and converted into catechin, which gives a bitter taste. Blocking sunlight increases theanine and reduces catechin, creating the typical taste of Gyokuro.
The characteristic seaweed-like flavor of Gyokuro is composed of dimethylsulphide, produced during the steaming process. The leaves are deep green compared to the yellowish-green of Sencha because the lack of sunlight increases chlorophyll production in Gyokuro leaves.
Hon Gyokuro tea garden
Fresh straw (left) vs. old straw (right). The quality of straw significantly affects the tea.
3. Cultivar and Plucking
Asahina Gyokuro consists of 4 cultivars, whose blending ratio is determined by the producer. The leaves are plucked by hand, so the tea bushes are not cut into a table shape but left to grow upright. The first flush is plucked from the end of April to the beginning of May, but for Hon Gyokuro, plucking occurs later, usually in mid-May. The plucking standard is 1 bud and 3 leaves. The third leaf stays on the tree longer and contains more minerals and polyphenols, essential for a strong flavor and thick body. Plucking is done after sunrise to avoid morning dew, which can cause the leaves to overheat during steaming.
Tea leaves at the Gyokuro garden just before plucking
Gyokuro leaves turn a deep green color
4. Processing
The process for Gyokuro is similar to Sencha, but Gyokuro leaves contain more moisture and are more tender, requiring extra care during handling.
Receiving the Tea Leaves
Tea leaves plucked from different gardens are segregated and assigned lot numbers for clear traceability.
Steaming
Gyokuro leaves are steamed for 20 seconds, shorter than Sencha, at high temperatures to ensure they are completely dried with no residual moisture.
Cooling
The leaves are quickly cooled and moisture evaporated to avoid secondary heating.
Pre-Rolling
The leaves are dried by agitating them under hot air, which also softens them.
Rolling
This process is conducted without heat. The machine moves in a circular motion with pressure, evenly distributing moisture. The leaves generate heat due to friction, so they are loosened regularly to release it.
Intermediate Rolling
A rotary dryer gently rolls the leaves to promote drying, reduce moisture, and twist them into a finer shape.
Final Rolling
The leaves are twisted into a needle shape with a back-and-forth motion combined with circular movements, resulting in high-quality, dark green, shiny, and firm Gyokuro leaves.
Drying
After final rolling, the leaves still contain moisture and need further drying to reduce moisture content to 5%. These leaves are called Aracha (crude tea). Aracha does not undergo firing, and compared to the finished product, the flavor is stronger and more bitter.
Beware of Keeping Tea in the Fridge
While tea lasts longer in the fridge, condensation when taken out can deteriorate its quality. Simple sealing methods are not sufficient. If you must store tea in the fridge, allow it to warm to room temperature for over 24 hours before opening. Rapid temperature changes can damage the tea leaves.
