We need “pesticides” to grow tea. Crops are susceptible to diseases and pests, so pesticides are used in cultivation for stable supply. Every crop has a different purpose of using pesticides. This article is about pesticides in the cultivation of tea.
Pesticides that are used for tea
pesticides that are used in tea cultivation are pesticides, fungicides, herbicide, etc. Fungicides are divided into the two types: Protectants for disease protection and therapeutic agents for disease treatment. The use of pesticides, regarding residue standards and the period and method of use, is strictly regulated by Agricultural Chemicals Regulation Act, Food Sanitation Act, Water Pollution Prevention Law, etc.
Diseases of tea
There are several diseases of tea. Infected parts can be fresh buds, leaves, roots, stems, or others depending on the case. While different cultivars are liable to different diseases, common diseases are anthrax, blister blight, Pythium red blight, Dendrophoma obscurans, Pestalotiopsis longiseta, etc. Anthrax in particular can be seen at tea plantations across the country because “Yabukita,” the representative cultivar of tea, is susceptible to it. Pesticides are effective against these diseases to some extent.
Pests of tea
Tea has 100 types of pests. There are so many, but only a dozen or so require control. Major pests include yellow tea thrips, Kanzawa spider mites, tea jassids, tea leaf roller, and white peach scales. Pest damage varies by pest types. Some suck the sap of tea trees, and others eat leaves, especially fresh buds. There is also one that blights stems and branches.
Advantages and disadvantages of Pesticides
The advantages and disadvantages of pesticides are as follows.
The basic disease prevention is to grow a disease-resistant cultivar, but it is unlikely that the chosen cultivar also makes large yields of good quality. To cover these shortcomings, farmers use pesticides. In addition, increased weeds take necessary nutrients for the growth of tea trees, so they sprinkle herbicides to prevent the growth of weeds. It also reduces labor for farmers suffering continuous shortage of hands.
To fulfill the purposes of pesticides, such as killing pests and removing weeds, they need to be violently poisonous. It is not only consumers but also the farmers sprinkling them who worry about health hazards. Furthermore, the use of pesticides is disturbing the ecosystem by acting only on specific pests and weeds, and inevitably causing negative environmental effects. Today’s pesticides are friendlier to the human body and environment than before. However, there are still many challenges.
Do you know how your daily tea is produced? This article provides a rough summary of the methods and manufacturing processes of teas in general. We will go through main processes from picking fresh leaves to shipment, two important phases of “Aracha (crude tea)” and “finishing” in tea manufacturing, and the difference in manufacturing process by the type of tea.
Main processes from picking fresh leaves to shipment
Tea leaves are grown at a tea plantation. At the picking season, fresh leaves are plucked. Then, after many manufacturing processes, they are shipped across the country and reach you. The manufacturing process differs by the type of tea, but the flow is divided into the two main phases of Aracha and finishing. Let us take a look at these two.
How to make Aracha
Fresh leaves of tea contain oxidative enzymes. The plucked leaves get oxidized by enzymes with time. The teas produced without fermentation (oxidation), such as green tea, go through heating treatment to deactivate enzymes in the fresh leaves. Then, the teas undergo processes such as rolling/twisting, fine rolling, and drying to become Aracha.
In contrast, the teas produced through fermentation (oxidation), such as black tea, need to be fermented well in a hot and humid fermentation chamber after withering and kneading. The teas, fully fermented and dried, become Aracha.
Fermentation starts, immediately after plucking, due to oxidative enzymes in the tea leaves. This fermentation refers to enzymatic oxidation, which is a little different from microbial fermentation. Note that some teas such as post-fermented teas are actually produced through microbial fermentation.
This process is to block fermentation by halting the activity of the enzymes through heating treatment. Main deactivation methods include the Mushi method (steaming fresh leaves) and the Kama-iri method (roasting in the pan).
In this process, pressured kneading equalizes the leaf moisture so that the ingredients get easy to come out.
This process is to shape the tea leaves by drying with heat and kneading in one direction.
This process is to further dry the leaves by thoroughly airing hot wind. Here comes Aracha.
In the phase of Aracha, the leaves are irregularly-shaped and not completely dry. They are not ready to be shipped as a product. So we need the finishing phase. Finishing includes sorting/shaping, firing, and blending in this order. Shipment follows measuring, checking, and packaging. Finishing enables long storage and enhances the tea flavor.
Aracha is sieved to remove fine stems and sort the leaves by the size. And the following processes such as cutting shape the leaves.
Drying once again with fire improves the shelf life of the leaves and brings out the tea aroma.
As the final adjustment, blending is to equalize the composition and quality of the tea. Measuring, checking, and packaging follow to ship the tea as a product.
Difference between tea types
Tea manufacturing process varies a little between types of tea. They are classified into the four types of “unfermented tea,” “half-fermented tea,” “fermented tea,” and “post-fermented tea” according to the extent of fermentation. In addition, “flowering tea” is a tea processed with these. Let us take a look at each of them.
Unfermented tea (green tea, matcha, etc.)
Unfermented tea is a tea whose plucked fresh leaves have undergone heating treatment prior to fermentation by the leaf oxidative enzymes. As a result, it remains unfermented. It keeps a fresh aroma and a clear green color. When heated, the enhanced fragrance yields an elegant flavor and aroma.
Half-fermented tea (oolong tea, etc.)
Half-fermented tea is a tea whose fermentation has been stopped at a suitable point. Unlike unfermented tea, the fresh leaves are withered before fermentation. As a result, aroma components produced by oxidative enzymes and the like yield a characteristic fragrance. It stands in the middle between green tea and black tea in terms of the degree of fermentation. According to the degree of fermentation, half-fermented tea is further classified into white tea (bai cha), yellow tea (huang cha), blue tea (qing cha/oolong tea), etc.
Fermented tea (black tea)
Fermented tea is a tea whose leaves have undergone a full fermentation by oxidative enzymes. As with half-fermented tea, the leaves are withered before fermentation so that oxidative enzymes produce various aroma components. Fermented longer than half-fermented tea, the tea takes on a characteristic glamorous fragrance. It is fermented tea, among the four classes, that is consumed the most in the word.
Post-fermented tea (Pu'er tea, etc.)
Post-fermented tea is a tea produced through fermentation by microbes, not by oxidative enzymes. Post-fermented tea changes its flavors with different microbes. Pu’er tea from China is a representative tea fermented by kōji-mold (aspergillus) and Goishicha from Kōchi Prefecture is a representative tea fermented by lactic acid bacteria.
Flowering tea (jasmine tea, etc.)
Flowering tea is a green tea, white, tea, blue tea, or other tea flavored with flowers and fruits. A representative example is jasmine tea, which is one of the most popular teas even in Japan with its elegant aroma.
Like green tea, “Hojicha (roasted green tea)” is a popular Japanese tea among many people. What on earth makes its distinctive pleasant aroma and smooth taste? This article guides you through the manufacturing process of “Hojicha.”
Features of Hojicha process
Hojicha is produced by roasting processed tea at about 200 degrees C until it turns brown. Its processing method was originally to enjoy low-quality tea and applied mainly to low-grade tea such as stem tea and Bancha (common tea). In general, Hojicha is graded high if it is from the Ichibancha (first picked tea) that is picked late in the first season. Another high-grade one is “Stem Hojicha,” a roasted high-grade stem tea.
What changes by roasting?
Roasting tea leaves produces “Pyrazine” so that the leaves take on a distinctive pleasant aroma. In addition, it lessens tea’s characteristic astringency and makes a smooth, easy-to-drink taste.
How to make Hojicha at home?
The original method requires a tool called “Horoku.” Here, we will show you an easy way that uses a frying pan.
1. Spread tea leaves in an unheated frying pan and start at medium flame.
2. Wait for a while before you start stirring
3. After an aroma starts arising, stir them with a wooden spatula carefully not to scorch them, and roast them to your preferred color. Now it is ready.
4. Brew the tea with hot water for a better aroma. Take enough time until its color appears a little too deep (approximately 30 seconds).
Today “Matcha” is loved throughout the world. It is made of a tea called “Tencha.” How much do you know about “Tencha?” This article guides you through how “Tencha” is manufactured and how it becomes “Matcha.”
Features of Matcha process and Tencha process
“Tencha,” the material of Matcha, is the only tea that skips the kneading process unlike Sencha (steeped green tea). For this reason, its Aracha (crude tea) takes shorter to manufacture than Sencha. However, its whole process takes time and effort as with Sencha, considering its leaves need to be ripened and ground in a mill.
From picking fresh leaves into shipment
The picked fresh leaves are processed into “Tencha” at first. Then it undergoes the finishing process to be shipped as “Matcha” across the country.
Tencha process is broadly divided into two phases of “Aracha” and “finishing.” Let us start from the “Aracha” phase.
Freshly-picked leaves contain oxidative enzymes. The enzymes immediately start fermentation (oxidation). This process is to deactivate their action with the heat of steam. Tencha is steamed shorter than Sencha. As a result, the leaves turn bright yellow-green and gain a distinctive scent called “ooika (covered aroma).” To make a deep-colored Matcha, the leaves should be steamed longer.
The leaves are put in a tea leaf blower. The 5-meter-tall machine repeatedly blows the leaves up and down, and cools them down. It can separate and arrange the cooled leaves in a single layer.
Rough drying (main drying)
Leaves are dried with hot wind of over 150 degrees C through a special drying oven. The layered oven has three conveyor belts. The leaves are dried rapidly on the bottom belt, blown up to the top belt, and dried gradually until they go down to the middle belt.
That’s all for the Aracha process.
The stems of Aracha are not fully dried so they are not good for making Matcha. The finishing process needs to follow. In the case of Tencha, this finishing process is also referred to as “Shitate (tailoring).”
The stem portions are cut off from the leaves using a machine called stem cutter. Furthermore, only the leaf portions of good-quality are sorted out and cut into the regular length, removing hard leaves and remaining stems.
The sorted leaves are blown and slowly dried. The wind can further separate the stem portions that have not been removed.
To make a preferred flavor and color, different types of Tencha are blended. This concludes the Tencha process.
Tencha under thoroughly controlled temperature and humidity is ground in a stone mill just before shipment. Finally the Matcha process is done.
Production areas of Matcha and Tencha
Uji City in Kyoto Prefecture and Nishio City in Aichi Prefecture are well-known as production areas of Matcha. Shizuoka Prefecture, Mie Prefecture, and Fukuoka Prefecture are also producing a lot of Matcha.
The birthplace of Matcha is said to be China, but today their Matcha production is much less.
Broadly speaking, unoxidized tea is processed in “the steaming method” or “the pan-roasting method” according to the way of deactivation. “The steaming method” is more common for Japanese green tea, while Chinese green tea is mostly processed in “the pan-roasting method.” The tea produced in “the pan-roasting method” is called “Kamairicha.” This article guides you through the features and process of “Kamairicha.”
Features of Kamairicha process
Kamairicha is a kind of unoxidized tea. It has undergone the deactivation of oxidative enzymes in the leaf immediately after plucking. It is featured by the process of “Kamairi (pan-roasting)” for deactivation.
From picking fresh leaves to shipment
Upon picking, the fresh leaves are processed up to the “Aracha (crude tea)” phase at a nearby site and transported to a finishing factory to undergo the “finishing” process. “Aracha” becomes a product through “finishing” to be shipped across the country.
How to make Aracha
Let us take a closer look at the process to make “Aracha”
The plucked tea leaves are thoroughly roasted in a hot iron pan of 300 degrees C. The heating and finishing processes rely on the experience and intuition of an expert.
The leaves are vigorously kneaded and dried with hot wind under an appropriate pressure. This process softens the leaves and reduces their moisture.
Rough rolling does not knead the leaves enough. Now the leaves are kneaded only with pressure, with no heat. This process equalizes the leaf moisture and breaks up the leaf cells so that the ingredients come out easily.
Rolling/twisting leaves the leaves shrunk and unshaped. By further kneading in hot wind, the leaves become easy to shape at the fine rolling process.
The leaves are dried and at the same time kneaded in one direction. This process gives green tea’s characteristic slender shape.
The leaves are dried in the sun to bring out their umami. They can be dried also with agitation in the pan. Now “Aracha” is ready.
In the phase of Aracha, the leaves are still irregularly-shaped and moist. It is difficult to maintain the quality. Here comes the need of the finishing process. In this process, “pre-firing, sorting/shaping, firing, and blending” take place in this order. Shipment follows measuring, checking, and packaging. Finishing enables longer storage and enhances the tea flavor.
Prior to sorting/shaping, the entire Aracha leaves undergo firing (roasting, etc.).
Aracha is sieved to remove fine stems and sort the leaves by the size. And the following processes such as cutting shape the leaves.
Drying once again with fire improves the shelf life of the leaves and brings out the tea aroma.
As the final adjustment, blending can equalize the composition and quality of the tea. Blending makes a well-balanced tea.
Kamairicha’s production areas and features
Kamairicha came from China to Japan around the 15th century. Most Japanese teas of that time were Kamairicha until the manufacturing process of Sencha (steeped green tea) was established. While “the pan-roasting method” is still the mainstream in China, Kamairicha accounts for less than 1 % of Japanese tea production. Main production areas in Japan are concentrated in Kyushu District, especially in Saga Prefecture, Nagasaki Prefecture, and Miyazaki Prefecture.
“Kamairicha” is featured by a pleasant aroma, called “Kamaka (pan aroma),” resulting from pan-roasting. It has a refreshing flavor with less astringency and attracts you by a light, transparent golden liquid color.
“Jasmine tea” is known for its elegant and gentle fragrance. Do you know how they flavor it? There are several processes to flavor it. Time and effort are spent. Jasmine tea is one of the teas called “flowering teas.” There are many other “flowering teas.” Let us take a look at various kinds of flowering teas and how tea leaves are flavored.
Features of flowering tea process
“Flowering tea” is a white tea (bai cha), blue tea (qing cha/oolong tea), green tea, or other tea flavored with flowers and fruits. Some are flavored by mixing raw flowers into tea leaves as with jasmine tea. Others are flavored by mixing dried petals into tea leaves as with osmanthus tea. Rose tea is brewed only with dried flowers, not using tea leaves.
From picking fresh leaves to shipment
In the case of jasmine tea, the plucked fresh leaves are processed to Aracha (crude tea) and then scented with alternatively layered flowers. Once flavoring has been done, flowers are removed and the packaged products are shipped.
How to make Aracha
It is common to use green tea, but in China white tea and blue tea are also used as follows.
Flowering tea is generally green-tea-based. Green tea has the property of “absorbing scents” and fits to make flowering tea more than other types of tea. In China, however, besides green tea, white tea and blue tea are also used for some types and brands.
1. Flavoring (In the case of jasmine tea)
Let us see the example of jasmine tea for the flavoring process.
You can add a scent only by directly mixing flowers with tea leaves. However, jasmine tea is valued higher when the leaves are flavored for a longer time. It may take several months to make a high-grade product.
Unopened jasmine flowers are chosen and hand-plucked one by one. The plucked buds are arranged and laid at a well-ventilated place until they open a little. Then, the buds are sieved to sort out only opening flowers. It is because opening flowers are giving out the strongest scent and suited for flavoring.
After sorting, the flowers and the tea leaves are placed alternatively in several layers to let the flower’s fragrance permeate the leaves.
During the flavoring process, the fragrance permeates the leaves with the flower moisture. It is important to keep a proper amount of moisture in this process.
The plucked flowers keep breathing, which generates respiration heat. The increasing heat withers the flowers and spoils the fragrance. To release the heat, the pile needs to be put down once. After the temperature decreases, the flowers are mixed into the tea leaves to uniform the fragrance.
The withered flowers and the tea leaves are separated through the siever. The tea leaves contain the moisture from the flowers now and need to be dried a little to stabilize the quality. The key is to dry slowly so that the flower scent is not blown off. The withered flowers are replaced by fresh ones. The processes from layering to separation are repeated. The number of repetition is generally three times, but a higher-grade product will require more.
Lastly, a small amount of fresh flowers are added and the packaged products are shipped. In fact, a higher–grade product is finished with fewer flowers. You can assume a product with a lot of flowers is low-graded.
About Jasmine tea and Flowering tea
Jasmine tea became the most popular because it was considered best-suited for flowering tea with its strong scent and good durability. It accounts for 80% of the production of flowering tea and still enjoys great popularity as a beloved flowering tea. Flowering tea was originally meant to entertain us with its fragrance, but some types of flowering tea plays the role of herbal medicines. In Japan, its health benefits are gaining publicity and various flowering teas are becoming available besides jasmine tea. In addition, an eye-pleasing type of “flowering tea” called “art tea” is coming on the scene. You can enjoy “flowering tea” in various ways. Many “flowering teas” are easy to drink. Why not find your favorite ones?
“Pu’ er tea” and “Goishicha” are seen more in our daily life these days. Do you know what makes their distinctive flavors? In fact, microbes play a role to yield those flavors and aromas. The term “fermented tea” that includes “Pu’ er tea” and “Goishicha” is from the method that utilizes microbes. Let us take a closer look at why it started being called “fermented tea.”
Features of fermented tea process
“Fermented tea” is a tea produced by fermenting the leaves with microbes.
In the world of tea, “fermentation” generally refers to oxidative fermentation, caused by enzymes. In contrast, the “fermentation” of fermented tea is caused by microbes such as mold and lactic acid bacteria.
Difference by type of microbes to be used
Two major types of microbes are used for fermented tea. One is mold (e.g. kōji-mold), which likes oxygen, and the other is bacteria (e.g. lactic acid bacteria), which dislikes oxygen. “Pu’ er tea” uses only mold, while “Awabancha” uses only lactic acid bacteria. “Goishicha” uses both of them through two-stage fermentation.
Fermented tea process
The manufacturing process of “fermented tea” varies by type of microbes used. The above “Pu’ er tea,” “Awabancha,” and “Goishicha” also have different processes each other. Let us see what differs with these three examples.
Pu’ er tea
“Pu’ er tea” undergoes fermentation for months or longer with the leaves pickled in kōji mold. In some cases, ripening takes more than ten years. Its flavor and health benefits change according to the ripening degree.
Oxidase deactivation by steaming
The plucked leaves are steamed to deactivate oxidative enzymes in the leaves.
The leaves are kneaded when they are still hot to uniform the leaf moisture so that the leaf ingredients get easy to come out.
2. Wo doi (Molding)
Add mold to the leaves to ferment under a specific controlled temperature and humidity. This process plays an important role because the tea’s quality, flavor, and aroma depend on its accuracy.
The hardened leaves are loosened by drying to finally become “Pu’ er tea”
“Awabancha” is produced through fermentation utilizing indigenous bacteria that originally live on or in a place like wooden buckets. It is an individual local tea produced in Tokushima Prefecture through many generations.
1. Deactivation by boiling
The plucked tea leaves are boiled to deactivate the leaf enzymes so that oxidative fermentation does not take place. This process is also effective to suppress the propagation of unwanted bacteria.
Kneading the leaves can evenly spread the leaf moisture so that the leaf ingredients get easy to come out.
The rolled leaves are stuffed in a big bucket with the boiled soup of the leaves added. Air is removed by poking the leaves from the top. The bucket is covered with the wooden lid and a heavy stone on it. Lactic acid bacteria start fermentation then. Pickling takes 2–5 weeks.
4. Drying after bucket opening
Once fermentation has finished, the leaves are taken out of the bucket and sun-dried. Then through sorting, thick stems and other unwanted parts are removed. Then “Awabancha” is ready.
“Goishicha” undergoes two-stage fermentation using both mold and lactic acid bacteria. It has been produced in Kōchi Prefecture since the Edo Period. The same method has been inherited since then. Indigenous bacteria are also inevitable for this tea. Bacteria that live in a storehouse or in a straw mat have been used for many generations.
1. Deactivation by steaming
Tea leaf picking for Goishicha is not leaf plucking but twig clipping. The leaves picked with twigs are steamed to deactivate oxidative enzymes in the leaves.
The steamed leaves are spread, piled, and left for about a week on a straw mat in the molding room. Fermentation starts then and lactic acid bacteria grow on the tea leaf.
Once the surface has been covered with mold, the leaves are stuffed into a wooden bucket. After adding the leaf juice from the steaming process, a heavy stone is put on it. Fermentation by lactic acid bacteria goes on as the leaves are pickled for several weeks.
Once fermentation has been done, the leaf bundle is taken out of the bucket and cut into 3–4-cm cubes with a special knife.
The tea cubes are arranged on a straw mat. After sun-drying, they become “Goishicha.”
The leaves turn black as they get dried. It is said that the term “Goishicha” is derived from the color and positioning of the leaves.
Do you know your daily oolong tea is called “semi-oxidized tea?” In fact, most of the Chinese teas are categorized as “semi-oxidized tea.” Let us take a closer look at “semi-oxidized tea” and its manufacturing process and methods.
Features of semi-oxidized tea process (Chinese tea process)
“Semi-oxidized tea” is a tea whose fermentation (oxidization) has been stopped halfway. Tea leaves originally contain oxidative enzymes. The enzymes start oxidative fermentation right after harvesting. Stopping fermentation (oxidization) by heating at a suitable timing lends a unique color and flavor to semi-oxidized tea.
Fermentation or oxidation?
In the world of tea, fermentation refers to oxidation by oxidative enzymes in the tea leaf, not microbial or bacterial fermentation as in miso and yogurt. Oxidation refers to the reaction of enzymes with oxygen to change the original ingredients. Some teas such as post-fermented tea utilize microbes for fermentation, but as a rule, fermentation in the tea industry means oxidization.
Different types of semi-oxidized tea
Semi-oxidized tea is classified according to the degree of oxidation as follows:
Types of semi-oxidized tea
· White tea (bai cha): bai mudan, baihao yinzhen, etc.
· Yellow tea (huang cha): mengding huangya, junshan yinzhen, etc.
· Blue tea (qing cha): oolong tea, tieguanyin tea, etc.
Different oxidization degrees
“White tea” is a tea made from very young downy leaves still covered by white hair. It is featured by the short oxidation process. In addition, it is the only semi-oxidized tea that skips the rolling process.
“Yellow tea” is a tea that has been slightly oxidized during the Aracha (crude tea) phase. It undergoes the oxidation process, “menhuang,” which utilizes the leaf’s heat and moisture after heating treatment.
“Blue tea” is a representative type of semi-oxidized tea. It is called “blue tea” from the appearance of oxidized leaves that have turned reddish-brown and unoxidized leaves that remain green mixed together. Oolong tea is also a type of “blue tea.”
From picking fresh leaves to shipment
Every tea manufacturing starts from tea leaf picking called “plucking.” In the case of Chinese tea, unlike Japanese tea, tea leaves with a wider opening are to be picked. The picked leaves undergo withering, oxidization, rolling, drying, etc. to become “Aracha” and go through the finishing process at a finishing factory to be shipped.
How to make Aracha
There are various steps according to the type of tea. For example, in the case of ordinary oolong tea, the manufacturing method consists of sun-withering (shaiqing), indoor-withering (liangqing), rotary oxidization (yaoqing), pan-roasting (shaqing), wrapping (bao rou), rolling, and drying in this order to become Aracha.
1. Sun-withering (shaiqing)
The leaves are sun-dried in fine weather to be withered. The withering tank’s hot wind is also used in case of bad weather, but sun-dried ones are graded better in general.
2. Indoor-withering (lianqing)
Sun-withering makes the leaf temperature higher. The leaves need to be spread and cooled down on the indoor shelf before going to the next process.
3. Rotary oxidization (yaoqing)
The leaves are rotated in a bamboo basket to damage the leaf edges. Enzymatic oxidization gets activated from the damaged parts. The edges turn reddish-brown, while the inside of the leaf remains green. Now the leaves are semi-oxidized.
4. Pan-roasting (shaqing)
Oxidization is stopped at a right moment by roasting the leaves in the pan. The mainstream is hand-roasting with a tilted pan, but machine-roasting is coming on the scene nowadays.
As with Japanese tea, the leaves are kneaded under pressure. The process evenly spreads the leaf moisture so that the leaf ingredients get easy to come out.
6. Wrapping (bao rou)
The tea leaves are wrapped in a cloth roughly about 20 by 20 inches and shaped by squeezing and narrowing down in a rolling way. This process and the following drying process are repeated about 20 times.
The tightened bundle gets loosened and dried to remove the leaf moisture. Drying should take place slowly so that the leaves will not revert to the original shape by rapid drying. Then, the leaves are kept in a hemp bag to be transported to a finishing factory.
The leaves become Aracha after drying, but the leaves at this phase are not enough to be a product. Aracha needs to undergo “finishing” at the end.
Aracha is slowly roasted for the final adjustment of the leaf moisture. Roasting to a preferred degree brings out a nice flavor.
This completes the oolong tea process.
Fertilizer" is used when growing tea.
Appropriate use of fertilizers can make tea aroma and taste to your liking.
In this article, we will explain the types of fertilizers and their merits and demerits in detail.
Fertilizers used for tea
The purpose of fertilizers used for tea is to produce a large harvest of high-quality tea leaves, and the necessary nutrients are applied. This is called "fertilization."
The main components of fertilizer are nitrogen (N), phosphoric acid (P), and potassium (K), which are called the three primary elements of fertilizer.
Since tea leaves are a crop rich in amino acids, nitrogen supply is essential.
Fertilizers can be divided into two main categories: chemical fertilizers and organic fertilizers.
What are the characteristics of each type of fertilizer?
Chemical fertilizers are made by chemically manipulating components essential for plant growth and increasing their concentration.
There are two types of chemical fertilizers: "simple fertilizers," which are made from single fertilizer components such as nitrogen, phosphate, and potassium, and "chemical compound fertilizers," which are made by mixing these components.
Organic fertilizers are fertilizers made from organic materials such as animal feces and food dregs.
Plant-based fertilizers are made from rapeseed, soybean, etc., and animal-based fertilizers are made from fish, fish, etc. There is also a type of fertilizer called "bokashi fertilizer," in which microorganisms ferment these materials.
Advantages and disadvantages of using fertilizers
The next topic is the advantages and disadvantages of chemical fertilizers and organic fertilizers.
Advantages of chemical fertilizers
Because the fertilizers are separated by component, you can use different types of fertilizers depending on what you want them to act on. In addition, fertilizer management becomes easier because you can choose the type and amount of fertilizer while watching growth.
In particular, since nitrogen determines the umami components of tea, the amount of nitrogen fertilizer can be adjusted to suit the desired umami of the tea.
Disadvantages of chemical fertilizers
Tea plants have a limited amount of fertilizer that they can absorb. Therefore, excessive application of fertilizers can cause tea plants to have trouble absorbing the fertilizers, resulting in lower yields and poor quality.
There are also concerns about the environmental impact of chemically produced fertilizers.
Advantages of organic fertilizers
Because of its high organic content, it provides food for microorganisms living in the soil and stimulates their activity. The products produced by the microorganisms improve the quality of the soil, which in turn enhances the growth of tea plants.
In addition, because the fertilizer is made from organic matter such as food, it is environmentally friendly.
Disadvantages of organic fertilizers
Compared to chemical fertilizers, organic fertilizers do not have an immediate effect, making the timing of fertilizer application more difficult.
Incorrect fertilizer management can delay growth and reduce yields, so constant attention to soil, climate, and growth conditions are necessary to manage fertilizers.
“Cover cultivation” is one of the tea cultivation methods. Tea leaves grown in this method are processed into “Gyokuro,” “Tencha,” and “Kabusecha.” Why are tea leaves grown in cover cultivation preferred to make these types of tea? This article provides the reason in detail.
What is cover cultivation?
Cover cultivation is a cultivation method in which tea trees with growing fresh buds are covered to avoid sunlight for a certain period. Photosynthesis in the leaf barely happens without the sun, so the fresh buds take a longer time to grow to become harder leaves. Picking time can be longer thanks to this process. In addition, the cover keeps the leaves warm so that they can be protected against frost and picked earlier. Good-quality tea is produced from the leaves that are “less hard and kept warm.”
Features of tea grown in cover cultivation
A tea leaf covered during cultivation takes on a distinctive grassy aroma called “ooika (literally cover aroma in Japanese).” An increased number of chlorophylls deepen the green color of the leaf.
The tea grown by cover cultivation has a bright green liquid color compared with the tea produced without covering. Its characteristic rich fragrance arising from the cover aroma and slightly astringent flavor entertains you well. The brilliant tint and light astringency are suited for the processing of “Gyokuro” and “Tencha”
Why does cover cultivation make tea more delicious?
The tea’s umami component theanine, when exposed to the sun, changes to the tea’s astringent component catechin. However, cover cultivation blocks sunlight and prevents theanine from changing to catechin, so the tea can store full of umami. Furthermore, the amount of caffeine, which is less bitter than catechin, increases by light shielding. As a result, the tea grown by cover cultivation provides a sweeter flavor with lighter astringency and bitterness than the tea grown without covering.
"Organic cultivation" is one of the methods of tea cultivation.
Do you know what organic cultivation is? Strict standards must be met before tea can be labeled as organically grown. In this article, we will explain in detail about organic farming.
What is organic farming?
Organic farming uses methods that "do not use chemically synthesized fertilizers or pesticides, do not use genetic modification technology, and reduce the environmental impact of agricultural production as much as possible."
Specifically, it refers to cultivation methods that do not use prohibited pesticides or chemical fertilizers and that take into consideration nature's natural ecosystems.
There is also pesticide-free cultivation, but it is not the same as organic cultivation because the regulations differ. Organic cultivation is subject to strict standards, not only in terms of whether or not pesticides are applied but also in terms of soil preparation and seed suppliers.
JAS certification is given to agricultural products and processed foods that meet the standards for organic cultivation.
Based on the JAS Law established by the Minister of Agriculture, Forestry, and Fisheries, a registered certifying organization conducts inspections. Only products that pass these inspections are allowed to be labeled "organic" or "organically grown.
When applying the JAS mark, the name of the inspection organization that conducted the inspection and the certification number must be indicated.
Organic Farming of Tea
Organic tea must be harvested from areas free of synthetic pesticides, synthetic fertilizers, and synthetic soil conditioners for at least three years and where the soil has been prepared with compost or other fertilizers.
If fertilizers are used, only organic fertilizers that meet the standards may be used. When organic farmers use fertilizers, they mainly use homemade fertilizers (fermented fertilizers).
During cultivation, farmers take the time and effort to harvest leaves appropriately to prevent a sudden increase in insects and diseases and to cut weeds to ensure that the tea plants are well nourished.
Features of Organic Tea
Because the tea leaves are grown in a near-wild state, the original flavor of the tea leaves is brought out to the maximum extent.
Although the aroma is strong, the bitterness and astringency are not too strong, and the tea has a moderate richness and a refreshing aftertaste.
When usual tea leaves are brewed in hot or cold water, agrochemicals also melt into the liquid.
Even though the amount is safe to our body, there are concerns about consuming agrochemicals for many years.
However, organically grown tea leaves are completely free of such concerns, and can be consumed safely even by those with chemical sensitivities.
In addition, by not using pesticides in cultivation, the tea is environmentally friendly and does not negatively impact the ecosystem. Therefore, it is expected to help maintain and stabilize agriculture in the future.However, organically grown tea leaves are completely free of such concerns, and can be consumed safely even by those with chemical sensitivities.
In addition, by not using pesticides in cultivation, the tea is environmentally friendly and does not negatively impact the ecosystem. Therefore, it is expected to help maintain and stabilize agriculture in the future.
In the early stages of conversion to organic farming, yields are unstable due to many pests and diseases.
Organic fertilizers are also challenging to handle, and their ingredients are less stable than chemical fertilizers, so you must constantly assess the condition of the soil and crops to manage fertilizers.
Because the tea plant is more susceptible to crop failure due to weather conditions and adverse effects of pests and diseases, it isn't easy to achieve stable production year after year in terms of yield and quality.
Without knowledge and skill and a long period of time for the soil to stabilize, obtaining stable yields with organic farming isn't easy.
Another disadvantage is that because herbicides are not used, weeding is required throughout the year to remove weeds that have grown between the rows, increasing the workload for farmers.
Did you know that green tea, black tea, oolong tea, and other teas we usually drink, which differ in taste, aroma, and color, are all made from the same tea leaves?
These teas have different tastes and aromas due to the differences in their production methods.
In this article, we will explain why black tea is called fermented tea and how the aroma of black tea is produced, along with the manufacturing process.
Characteristics of manufacturing process of oxidized tea (black tea)
The fermented tea is tea made through complete enzymatic fermentation.
Contrary to unoxidized teas such as sencha and deep steamed sencha, fermented tea is oxidized and fermented using the oxidizing enzymes in the tea leaves.
Initially, it was an "ingenious process (handmade process)" that originated in China about 200 years ago, but nowadays, it is often made by machine.
There are two main production methods: "orthodox" and "unorthodox," A combination of the two has also been produced.
Here we introduce the traditional "orthodox" method.
Fermentation or oxidation?
Fermentation, as used in the tea world, refers to oxidation caused by oxidizing enzymes in tea leaves, as opposed to fermentation caused by microorganisms (bacteria) such as miso or yogurt.
Oxidation is a reaction in which oxygen and enzymes combine to change the original ingredients.
Microorganisms, such as post-fermented teas, ferment some teas, but the tea industry refers to this oxidative fermentation as fermentation.
From plucking fresh leaves to shipping them
Tea leaves are grown in a tea plantation. The tea leaves plucked in the picking season become Aracha (crude tea) after kneading and drying. Then, through “finishing,” the tea becomes a product to be shipped.
How to make Aracha
The plucked fresh leaves undergo the processes of withering, rolling, ball breaking/sieving, oxidation, and drying in this order to become Aracha. Then, after the finishing process, the tea is shipped across the country.
Wilting the fresh leaves to remove the water content evenly is called wilting.
In the past, the leaves were often dried in the shade, but nowadays, "artificial wilting," in which wilting is carried out in a wilting tank with a large amount of warm air, is used.
The cells of the tea leaves are broken down and shaped by the oxidizing enzymes in the leaves.
When the oxidizing enzymes are exposed to oxygen in the air, they are activated, and catechins, pectin, and chlorophyll undergo oxidative fermentation. These oxidative enzymes are the key elements that create black tea's aroma, taste, richness, and watercolor and lead to the differences between black and green tea.
The tea is fermented for 45 to 90 minutes. Still, to prevent the oxidative fermentation from advancing too quickly, the tea is put through a ball breaker to suppress the fermentation process, cooled, and then repeatedly rubbed again.
3. Ball breaking/sieving
Since the tea leaves clump together during the rubbing process, they are unraveled to allow for average exposure to air, which further promotes oxidative fermentation. The tea leaves are put through a ball unraveling machine during this process every 20 to 30 minutes.
The tea leaves are sieved through a mesh, and those sieved down are called "under the sieve" and transferred to the following process. The larger leaves on the sieve are called the "top of the sieve" and are returned to the twisting process.
In a fermentation chamber with room temperature set at 25-26°C and humidity at 90%, tea leaves are spread evenly to a thickness of 4-5 cm and left to ferment for 2 to 3 hours. During this process, the green leaves turn a bright reddish-bronze color, and a tea-like aroma waft through the air.
However, if the tea leaves ferment too much, the original aroma of the tea will be spoiled, and the watercolor will turn black. Hence, it is necessary to determine when to stop the fermentation process.
Tea leaves at the end of fermentation still have a high water content, and if they are left as they are, fermentation will continue, so they are placed in a dryer and dried with hot air at a temperature of around 100 degrees Celsius. Drying inactivates oxidative enzymes and reduces moisture to less than 5%.
The tea after drying is already called “Aracha,” but it cannot be shipped as a product yet. In the finishing phase, it undergoes sorting/shaping and blending in this order to be ready to ship as a product.
6. Sorting (Grading)
Aracha goes through a sifter several times to be sorted by the size and shape. Sorting classifies the tea leaves into grades. This grade is called “leaf grade.”
The final step is blending the leaves. Over 20 types of tea leaves are used, but the purpose is not to mix various kinds. It is to stabilize the quality by choosing teas from the same production area. Blending influences the price of each black tea, and what matters is how to suit consumer tastes by blending.