All About Shading in Japanese Tea Cultivation

Hello! Genki desuka (How are you doing)?

Today, I would like to delve into the topic of shading and shaded teas. If you enjoy drinking gyokuro, kabusecha, or matcha, you have already tried teas that have been cultivated through different shading techniques.

In fact, Yunomi tea merchant Ian Chun has previously touched on this topic in an earlier blog post (Check out: How does Shading affect the Type and Quality of Tea?). Today, we will expand a bit on this topic as shading becomes more common in the world of Japanese tea! 

 

What is Hifuku Saibai ? 

Shade growing cultivation [Japanese: 被覆栽培; hifuku saibai] is a method of cultivating tea plants by shading them prior to harvest. This shading blocks a certain amount of sunlight from reaching new tea leaves for a certain period of time, changing the tea leaf. Also referred to as "covering" [被せ; kabuse] in the tea industry, it is a cultivation method that is employed to make tea leaves more tender, more green, with greater umami flavor and less bitterness / astringency—qualities that increases the quality of the resulting tea.

In general, the teas that are cultivated utilizing the cover cultivation method include gyokuro, kabusecha, and tencha. Gyokuro and tencha are made by being shaded for approximately 20 days or more, and kabusecha is cultivated by a shorter shading period lasting about 10-14 days.

In contrast to these teas, "sencha" typically refers to non-shaded tea (grown in full sunlight). However, you can also say sencha refers any green tea where the leaves are steamed and then rolled (so this excludes tencha where the leaves are not rolled). So sencha can be shaded a few days to increase its quality a little, or shaded and unshaded leaves can even be blended to either increase the quality or increase the volume. However, since kabusecha and gyokuro named teas fetch a higher price, there is little point in naming a gyokuro a sencha tea.

 

A Shady History

When did shading as a technique begin? Shading was a technique which began in the latter half of the 16th century with the original purpose being to protect the early tea leaf sprouts from frost damage when the temperatures still dropped low in early spring.

With time and experience however, tea farmers soon began to notice that the quality of the tea which had been shaded for frost protection was better—greener with a better aroma and flavor. Farmers also noticed that tea bushes grown surrounded by forest (i.e., more shade) and in forested areas also produced higher quality tea. In this way, shading grew into a technique which was utilized to produce high quality tea.

In 1835, a young Yamamoto Kahei VI (the 6th head of Yamamotoyama in Edo, the old name for Tokyo) while visiting Uji, Kyoto, to learn about tencha production at farmer/producer Kinoshita Kichizaemon, rolled the in-production tencha leaves in little balls and dried them. He took them back to Edo and called them Tama no Tsuyu (balls of dew, written 玉の露 -- the kanji then becoming gyokuro 玉露). This history of gyokuro continues from there as Eguchi Shigejuro 江口茂十郎 from Uji realized that the sweetness came from the shading of the leaves during cultivation.

Read more in Japanese

 

Why bother with shading? 

Considering the fact that plants need water, sunlight and good soil, it may seem rather strange that we would want to limit the amount of sunlight that the tea bushes receive. But, just as a healthy amount of stress (eustress) can be good for human performance, stressors such as limiting sunlight can also influence the growth and chemical processes of the plant in a positive way. In fact, shading has advantages with respect to three essential aspects of tea: taste, aroma, and color. 

 

Taste: Maximizing Umami 

Perhaps the most significant reason for cover cultivation lies in obtaining the umami flavor that Japanese tea is known for. You may have heard of L-theanine amino acid, the chemical component that is responsible for the umami flavor in Japanese tea.

When exposed to sunlight however, theanine transforms to catechins, increasing astringency and bitterness. When shaded however, a greater amount of L-theanine in the leaves is retained, maximizing the amount of umami. In contrast, the amount of caffeine (which has a more refreshing bitterness in comparison to catechins) will be enhanced with shading. In this way, teas that are cultivated with shading tend to be low in astringency and bitterness and the tea drinker may better appreciate and access the umami and sweetness!

 

Unique Green Seaweed-like Aroma

By shading the tea leaves, a unique green seaweed-like scent that is referred to as a covering aroma [被覆香り; hifuku kaori;  覆い香り; ooi kaori] will be present in the tea leaves. This scent is created by making an aroma component called dimethyl sulfide. While too much dimethyl sulfide will lead to an unpleasant odor, if it is a small amount, it mixes with the other aroma components to create a refreshing and pleasant aroma of tea. The "covering aroma”, which can be said to be proof of the cover cultivation, is a scent which is representative and proof of high quality tea. Because kabusecha is shaded for a shorter period of time in comparison to gyokuro and matcha, this unique aroma will generally be weaker in a kabusecha. 

However, the "covering aroma” can mask the scent of the actual tea leaves and cultivar specific characteristics, so it may not be suitable if the tea farmer is hoping to retain a unique or characteristic aroma.

 

Beautiful Color

Another aspect that is enhanced through shading is the color of the tea leaves. Because the shaded tea plants have to do photosynthesis with less sunlight, the plants must produce more chlorophyll to do the same amount of photosynthesis. The greater amount of chlorophyll, in comparison to a non-shaded tea plant, produces a dark but bright, beautiful lush green color. Moreover, because shaded tea leaves try to increase their surface area to obtain the most amount of sunlight possible, shaded tea leaves tend to be softer and more delicate, making them easier to process into an elegant and fine looking tea.

Kurihara Tea Garden Heritage Gyokuro

Kurihara Tea Garden’s heritage gyokuro tea leaves shining with life and color!
 

How Shading is Done: Different Types of Shading Approaches

Now that we’ve talked about some of the benefits of shading, I would like to also touch on the different approaches that are used for shading ranging from traditional to current methods. While we will go into the details of these different types, each method is used similarly. That is, to produce high-quality tea (taste, aroma, color), prolong the harvest period, as well as to protect the tea bushes from frost.

 

The Traditional Honzu Technique [本簾(ほんず)被覆; honzu hifuku

This is the traditional shading method for ceiling shelf covering, it is almost never applied directly onto the tea bushes. Today, this method is utilized to produce very high quality gyokuro and tencha (used for matcha). A key characteristic of the honzu technique is that the shading is done with organic material such as straw, bamboo or reeds. With this approach, tea farmers gradually increase the amount of shading by adding more material to the roof every few days, increasing the percentage of sunlight that is cut off over time.

Kuma Tea Garden's Traditional ShadinKuma Tea Garden's Traditional Shading 

To illustrate an example, 50% of reeds could cover the entire tea field during the first 7-10 days (i.e., sunlight is blocked 55-60%). The subsequent step would be to layer 600-700kg of rice straw, evenly spread on top of the reeds, which will block 95 - 98% of sunlight, for approximately 10 days. At Yunomi, when the traditional honzu technique is applied, we call it “Heritage Grade” (e.g., Kurihara Tea #16: Competition Grade Saemidori Heritage Gyokuro Green Tea).  

 

Spring harvest scene from the Kurihara Tea Farm to produce their heritage grade gyokuroSpring harvest scene from the Kurihara Tea Farm to produce their heritage grade gyokuro. While it is rare to come across tea farmers utilizing the traditional approaches, some tea farmers will go through the labor intensive process to enter competitions and make the finest quality teas. Photo by Kurihara Tea Farm (Yame, Fukuoka Prefecture, 2020). 

 

Shading with straw, bamboo, or reeds provides the ideal shade for the tea bushes (Just imagine how nice it would be to be present with tea bushes that are underneath natural shading!). Unfortunately, this traditional technique of shading requires intense labor as the tea farmer needs to gather the shading materials and they must maintain the shading structure in optimal condition during the growing season. For this reason, it is a technique that is now rarely employed. In fact, if you have visited the tea fields during early spring time in Japan, you may have come across a different and more common type of shading - black synthetic fiber material that covers the tea fields. This shading approach with black synthetic fiber material is called kanreisha [寒冷紗] in Japanese. Different types of fiber are available with varying opacity. Thus, in comparison to the uneven shading that may occur with the honzu technique using natural material, with synthetic fibers the tea farmer is able to regulate the obscurity of his shade grown tea bushes more, accurately, uniformly and effectively.

 

Wazuka, black synthetic fibre material - Moe Kishida

Close up of the black synthetic fiber material used for shading; Wazuka, Kyoto Prefecture. 

 

The black synthetic fiber material is generally applied to dual-layered shading method, tunnel shading method, or with direct covering. We will elaborate on each of these structures below: 


The Dual-layered Shading Method [棚型二段被覆; tanagata nidan hifuku] is similar to the traditional honzu technique in both structure and purpose. First, the construction of this shading method is a simplified version of the honzu technique. It is built on a shelf-like construction of metal bars. Secondly, the dual-layered shading method is used for the production of gyokuro and tencha and additional layers can be applied on top of the same structure to progressively limit light. Although shading with organic materials requires the structure to be built and taken down after each harvest season, with the dual-layered shading method, the synthetic fibers can remain rolled up in the field throughout the entire year giving the producer greater flexibility with respect to use of shading for purposes such as temperature regulation and protection from frost/cold depending on the time of year.

While the dual-layered shading method is clearly easier to maintain in comparison to the traditional technique, there are a myriad of benefits of utilizing the traditional approach. As you can imagine, with honzu shading, the natural material used for shading allows the tea plants to breathe, which allows for better airflow. Further, the aroma of the straw (mmm!) becomes present in the air that the tea leaf absorbs, adding to the taste of that tea a unique trait that can only be obtained under organic material. When it rains, it is believed that the raindrops that have managed their way through the thick layer of straw will carry with them particles of nourishment that the straw has bestowed onto them, which they in turn deliver to the shade grown tea leaf and soil. The straw itself, after it has been used on top of the tea garden, is also used as a means of fertilizer. Although natural shading cannot be re-utilized like the synthetic fiber material, it does serve other meaningful purposes. That is, after it has served its primary purpose of shading, the straw is dropped into the tea field and layered out in-between the tea bushes. The straw then serves an essential role in the regulation of soil temperature of the tea field, which minimizes the growth of weeds and grasses, and, as it decomposes, makes its way into the soil to return as nourishment for the subsequent year’s new buds (does this remind you of chagusaba?).

 

Tunnel Shading Method  [トンネル被覆; tonneru hifuku]  

Mainly used for the production of kabusecha (lightly-shaded tea), with this approach, only one layer of synthetic fiber material is applied over glass fiber poles (8-10mm in diameter) that are bent in an arc shape, thus giving the canopy a tunnel shape. With this approach, the covering has a shading rate of 60 to 75%, and to make kabusecha, the shading is maintained between 10-14 days just before harvesting. 

A downside to this approach is that it tends to be rather time consuming for tea farmers to set up the poles and then to put the shading over the poles. The majority of tea farmers prefer the direct shading method. Check out the tunnel shading method here (Japanese link)

 

Direct Shading Method  [直接被覆; chokusetsu hifuku

The least time consuming and most economical shading method that is used today for the cultivation of shaded teas (ranging from normal gyokuro, kabusecha, tencha, and even sencha). Because it is the most common, if you have visited a major tea producing region in Japan, it is likely that you have come across this type of shading. This approach of shading is similar but more simplified in comparison to the tunnel shading method, as the tea farmer simply lays the black synthetic fiber directly on top of the tea bushes.


Kuma Tea Garden - Direct Shading
Kuma Tea Gardens in Yame, Fukuoka Prefecture setting up their Direct Shading. 

 Kiroku Tea Gardens - Direct ShadingKiroku Tea Garden's directly shaded tea bushes (to left) in Wazuka, Kyoto Prefecture.  

 

The use of matcha for food began around the 1980’s followed by the demand for matcha for ice cream and beverages increasing in the Heisei Era (1989-2019). The popularity of matcha for both Japanese and Western consumers is one of the major factors leading to a significant increase in the production of shaded tea. Because the matcha produced for processing generally requires lower quality tencha, the direct shading method is applied to reduce costs for production. With time, the direct shading approach is predicted to continue expanding in the tea industry. 

 

Okay! That will be all from me on shading and Japanese tea. I hope that you were able to discover something new with respect to this topic. If any additional questions arise, don't hesitate to leave us questions/comments. Shading is an art of Japanese tea cultivation and I hope that you will be able to enjoy different shades of Japanese teas utilizing all of your senses!

Art of japanese teaGyokuroHifuku saibaiKabusechaMatchaMoe kishidaShadingTea cultivationTenchaThiamineUmami

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