Interesting Facts About The Japanese Tea Shading Process

Covering Process of Japanese Tea Plants

Covering culture or shading of tea plants has been in use since the early ages, and it was developed to save the tea leaves from frost. In modern days, farmers use the covering or shading process to achieve certain characteristics in tea for a specific period. The covering process varies in days for different tea and makes it different in flavor and aroma.

Tea came to Japan around the 12th century and became popular due to taste and health benefits.

Later in the 15th-16th century, the farmers started to cover the tea plants in the winter season. They saw that the cold winds destroy the growing leaves and found a solution in the covering process without knowing the shading effect. They would cover the crops when young leaves sprout to protect them before harvesting.

Farmers later realized that the covered tea leaves had a rich umami flavor and much less bitterness than usual tea. Later, this practice became popular to get the desired taste in tea and has made several variations. The covering process helped in discovering matcha green tea, which instantly became popular more than other varieties.

Shading is later classified into three types, ceiling shelf covering, simple tunnel shading, and direct covering. Each kind is used for the same purpose, to prolong harvesting period, protect crops from frost, and produce high-grade tea. In-ceiling shelf covering, a structure is made with bushes or straw above tea plants to filter the sunlight and let the plants grow high and bright in color. In other methods, plants are covered with see-through cloth a few weeks before plucking to get a rich tea taste. Lastly, some plants are entirely covered from the sun for specific days to produce high-quality and full benefits tea.

When talking about covering culture, one should not forget to mention Matcha, which was literally discovered due to this process. Before the grinding process, the loose tea form is called Tencha which is widely popular in Japan. Each year, four or six weeks prior harvest, a traditional covering process known as Tana is used. In it, the green tea plant is covered with straw mats or vinyl sheets a few feets above. Due to lack of sun, you see lighter green tea leaves due to the concentration of chlorophyll. This method is mainly responsible for the sweet umami flavor and plentiful health benefits.

Nowadays, not all green tea plants go through the covering process because each has its own taste, color, and aroma. Kabusecha literally means to cover, and it is the most common and widely known tea, which has a covering process for nearly three weeks. Gyokuro is another finest tea in Japan which is grown under a ceiling-shelf covering.

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Covering Process of Japanese Tea Plants — Frequently Asked Questions

What is the covering process for Japanese tea plants?

The covering process — also called shading — is a cultivation technique in which Japanese tea plants are protected from direct sunlight for a specific period before harvest. The covering is achieved with straw mats, netting, or vinyl sheets placed over the plants. The reduction in sunlight changes the chemistry of the tea leaves: more chlorophyll for vibrant color, more L-theanine for umami sweetness, and fewer catechins for less astringency. The covering process is what distinguishes premium teas like Matcha, Gyokuro, and Kabusecha from ordinary Sencha.

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When did the covering process originate?

The covering technique was developed in Japan during the 15th and 16th centuries, originally as a practical way to protect young tea leaves from frost damage and cold winds. Farmers would cover the plants just before sprouting in late winter. They eventually noticed that the covered leaves produced a tea with richer umami and significantly less bitterness than uncovered leaves. The discovery transformed Japanese tea production — covering shifted from a protective measure to a deliberate flavor-creation technique, eventually leading to the creation of Matcha.

What are the types of tea plant covering?

Three main types of shading are used in Japanese tea production. Ceiling shelf covering builds a structure of bushes or straw above the tea plants to filter sunlight, used most often for Gyokuro and Tencha. Simple tunnel shading covers plants with see-through cloth or netting for a shorter period before plucking. Direct covering wraps the plants entirely from the sun for specific days, used for the highest-grade teas. Each method achieves the same chemical effect — reduced sunlight, increased L-theanine — but at different intensities and durations.

What is the Tana method for Tencha cultivation?

Tana is the traditional ceiling-shelf covering process used specifically for Tencha (the leaf form of Matcha before grinding). Four to six weeks before harvest, the tea plants are covered with straw mats or vinyl sheets supported a few feet above the plants. The lack of direct sun causes the leaves to develop a lighter green color due to concentrated chlorophyll, an unusually high amino acid content, and the sweet umami flavor that Matcha is known for. Tana is what makes the resulting Tencha — and the Matcha ground from it — distinctively rich and sweet.

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Which Japanese teas use the covering process?

The covering process is used for the premium tier of Japanese green tea. Matcha — discovered through covering — is the most famous example. Gyokuro is grown under ceiling-shelf covering for about 20 days. Kabusecha — whose name literally means "to cover" — undergoes a shorter covering of around three weeks. Tencha (the precursor to Matcha) uses the Tana method for four to six weeks. Ordinary Sencha and the everyday teas like Bancha and Hojicha are not covered, which is part of what gives them their grassier, more astringent profile.