What Is Matcha? 

Definition of Matcha

In recent years, we’ve seen cases where products that cannot truly be called matcha — simply powdered green tea — are sold as “matcha.”
Ordinary powdered green tea lacks the deep umami and richness that are unique to matcha.

So, what exactly is matcha?

Matcha is a powdered tea made from Tencha green tea.
After the spring buds begin to sprout, the tea plants are cultivated under shade for approximately 20 days or longer, then harvested.
The harvested leaves are steamed, dried in a tencha drying furnace, and then stems, veins, and other non-leaf parts are removed.
The remaining leaf material is finally ground into a fine powder using stone mills or similar milling methods.

The quality of matcha varies greatly depending on the cultivar, cultivation method, harvesting method, processing, and milling techniques.

① Types of Tea Cultivars

Nearly 100 tea cultivars exist in Japan (for detailed explanations of cultivars, please refer here).
Among them, cultivars developed in Kyoto—commonly referred to as Kyoto cultivars—are particularly well suited for shaded teas such as matcha and gyokuro.

Kyoto cultivars generally exhibit:

• High tolerance to shading
• Strong umami and aroma when grown under shaded conditions
  
  

Representative cultivars include: Tenmyo, Hoshun, Gokou, Ujihikari, Ujimidori, Samidori, Asahi, Komakage.

② Shaded Cultivation

By reducing sunlight through shading, the conversion of theanine (an umami-producing amino acid) into tannins (which cause bitterness and astringency) is suppressed, resulting in tea leaves with higher theanine content and stronger umami.

Because the tea plants are grown under limited light, the leaves increase chlorophyll production to enhance photosynthesis, resulting in a more vivid green color.
In addition, shading promotes the development of the characteristic “ooika” aroma, often described as a seaweed- or nori-like fragrance (for more details on shaded cultivation, please refer here).

There are three main shading methods, each of which affects quality differently.

a. Honzu Shading

The most traditional method, used for the highest-grade matcha and gyokuro, involves covering the tea field with reed screens (yoshizu) and further shading them with straw.

Because ordinary reeds cannot support the weight of straw, thick reeds harvested from Lake Biwa are used to make the reed screens.
During the first approximately 10 days of the shading period, reed screens are laid over the overhead structure.
During the latter approximately 10 days, straw is additionally spread on top of the reed screens, creating a double-layer shading system.

This method allows gradual adjustment of shading intensity according to leaf growth.
Shading with reeds and straw prevents heat from accumulating inside the structure and filters sunlight in a way considered optimal for high-quality tea production.

Reed screens must be replaced approximately every five years, and this method requires the greatest labor and cost.
Nevertheless, the highest-grade matcha and gyokuro are cultivated using this technique.

Traditionally, the sides of the structure are also enclosed with reed screens; however, due to the labor involved, the sides are often covered with shading nets instead (photo source: Kyoto Prefectural Government).

b. Overhead Shading Structures

In this method, poles and wires are used to construct a framework over the tea field, and black shading sheets are hung like curtains over the top and sides.
Neither straw nor reed screens are used.

Because this method is significantly more efficient and economical than honzu shading, many producers have transitioned from honzu shading to overhead shading structures in recent years.

There are single-layer and double-layer shading structures.
Black shading nets typically provide approximately 90% light reduction.

However, constructing these structures requires substantial investment, and ride-on harvesting machines cannot be used due to the fixed framework.
For these reasons, an even simpler method—direct covering (c)—has become increasingly common.

That said, as with honzu shading, overhead shading structures prevent shading materials from directly touching the young shoots, reducing stress on the leaves.
This allows shading to begin at an early stage, improves heat ventilation, and enables the cultivation of high-quality tea leaves.
Double-layer structures also allow for gradual shading adjustments.

(Photo source: Kyoto Prefectural Government)

(harvesting in Tana)

c. Direct Covering

In this method, shading nets are placed directly over the tea plants.
Because it can be applied regardless of terrain or harvesting method, it has become widely used in recent years.

Since the nets are placed directly on the plants, shading is applied only after the shoots have grown to a certain extent.
In particular during summer, black sheets provide effective shading but tend to trap heat, which can damage the leaves.
As a result, quality is generally lower compared to honzu shading and overhead shading structures.

On the other hand, because direct covering does not require large structures or major investment, most matcha currently distributed worldwide is produced using this method.

③ Harvesting Methods

a. Hand-Picking

As the name suggests, this method involves harvesting new shoots entirely by hand.
Tea gardens used for hand-picking are trained in a natural shape, and harvesting is performed only once in spring.

After the spring harvest, the tea bushes are pruned deeply to restore vigor by autumn, enter dormancy in winter, and then produce new spring shoots that are harvested by hand using experience and skill.

Because contamination with old leaves is avoided, this method yields the highest quality tea.
However, it is extremely labor-intensive.
Even experienced workers typically harvest only about 10 kg of fresh leaves per day.
In depopulated and aging rural areas, securing sufficient labor remains a major challenge.

b. Two-Person Hedge Trimmer Harvester

This method uses an arch-shaped machine with automatically moving blades, operated by two people, to harvest new shoots from well-trimmed tea fields.

Approximately 120 kg of fresh leaves per hour can be harvested.
Compared with hand-picking, this method is roughly 50 times more efficient in terms of hourly output.

In mountainous terrain where ride-on harvesters cannot be used, this is the most common harvesting method.

If the cutting depth is too deep, old leaves and debris may be included.
If it is too shallow, only the tips of new shoots are harvested, reducing yield.
Harvesting on steep slopes and complex terrain requires considerable skill and physical strength.

Compared with hand-picking, leaf damage is more likely to occur, which can affect quality.
In addition, pre-harvest trimming and field maintenance are critically important to maintaining quality.

c. Ride-On Harvesters

These machines straddle tea rows using crawler tracks, with cutters positioned underneath to harvest the leaves.

Because the machines may tip over on steep slopes, they can be used only in areas with gentle terrain.
Most are operated by a single person, and the most advanced models can automatically follow pre-programmed routes.

Harvesting capacity is said to reach approximately 600 kg per hour, enabling significant labor efficiency.

Although continuous improvements are being made, their use is limited in traditional high-grade tea regions characterized by valley or mountainous terrain.
They are also unsuitable for tea fields with overhead shading structures.

Source: Kagoshima Prefectural Government


Source: Ministry of Agriculture, Forestry and Fisheries (MAFF):
“Robot Tea Harvester” Using an Unmanned Autonomous Operating System

④ Primary Processing (Tencha Processing)

Fresh leaves are processed through steaming and drying to produce tencha.
This primary processing is generally carried out by tea farmers, and many sell tencha in this unrefined state to wholesalers in Uji.

Steaming halts oxidative fermentation.
Insufficient steaming results in leaves that deteriorate easily, while excessive steaming reduces aroma.
Adjusting steaming conditions according to leaf characteristics requires technical expertise.

After steaming, the leaves are:

• Agitated to remove moisture
• Properly cooled
• Spread and loosened to allow heat to pass evenly during drying

a. Horii-Style Tencha Drying Furnace

This drying method was developed approximately 100 years ago by Mr. Horii in Uji and uses brick furnaces.

The brick furnace is heated to nearly 200°C, and the tea leaves pass through the furnace over approximately 30 minutes, drying gradually.
The bricks emit far-infrared radiation, enabling slow and uniform drying that preserves umami and aroma.

Traditional tencha factories in Uji use this Horii-style furnace.
Processing capacity varies by factory but is generally 80–100 kg of fresh leaves per hour.

b. Net-Type Tencha Drying Furnace

This newer furnace was developed to improve efficiency.
It uses stainless steel mesh to generate high-temperature hot air and radiant heat, aiming to replicate conditions similar to brick furnaces.

It has increasingly been adopted in large-scale production areas, particularly in Kagoshima.
Large machines can process up to 400 kg of fresh leaves per hour.

⑤ Secondary Processing (Refining and Milling)

After purchasing crude tencha, processors perform refining to remove stems, veins, and other non-leaf components.

If this step is insufficient, clogging may occur inside stone mills, or white fibrous material from stems and veins may contaminate the powder.
High-precision sorting is therefore essential for producing high-quality matcha.

Re-drying may also be performed according to consumer preferences to enhance aroma.

a. Stone Milling

The finest matcha is milled using stone mills made from Aji stone (granite) from Kagawa Prefecture.
The mills are connected to motors and operate continuously.

Only about 40 g per hour can be milled per stone.
Large producers operate dozens to hundreds of identically sized stone mills simultaneously.

Stone mill dressing (resharpening the grooves) requires specialized skill.
Only a limited number of craftsmen in Kyoto possess this expertise, and adjustment is typically required once every four years.

The groove patterns differ from those used for soba or wheat milling; only stone mills specifically designed for matcha can produce fine, vividly colored powder.

Because stone mills do not overheat even during long operation, the gentle warmth generated during milling is said to enhance aroma.
Microscopic observation shows that stone-milled particles retain angular shapes, unlike those produced by ball mills.

For high-concentration preparations such as koicha (thick tea), stone-milled matcha allows stronger flavor perception on the palate and is therefore considered more suitable.

b. Ball Milling

A ball mill consists of a stainless steel cylinder containing ceramic balls and tencha leaves.
The cylinder rotates via a motor, and the balls grind the leaves.

Depending on size, approximately 15 kg per day can be milled, dramatically improving efficiency.
However, continuous rotation generates heat, which can degrade flavor and quality.

Although the powder can be milled to 10–15 microns and is relatively uniform, stone-milled matcha is generally preferred for preparing thick tea.

c. Bead Milling

A more advanced form of ball milling, bead mills use ceramic or stainless steel beads inside a stainless steel cylinder.

A water-cooled outer layer surrounds the cylinder, cooling the interior and reducing noise.
Because internal temperatures remain low, quality is preserved during milling.

Bead mills enable high-speed milling at approximately 15 kg per hour, with even higher efficiency in large-scale models.

⑥ Harvest Season

Spring

In climates with four distinct seasons, such as Japan, spring-harvested tea is overwhelmingly superior in quality.

During winter, tea plants enter dormancy and store nutrients.
With the warmth of spring, these nutrients are transported into new shoots, resulting in tea with high amino acid content.

Large day–night temperature differences and morning fog in valley terrain further help preserve amino acids.
In Kyoto, shading for approximately 20 days is common, depending on weather conditions.

At the same time, frost risk exists; if new shoots are damaged by frost, yields decrease dramatically.
Spring tea, known as first flush or shincha, represents the highest quality.

For details on harvest timing and quality, please refer here.

Summer

After the first harvest in May, the bushes are pruned, and new shoots grow again around July.
Due to intense heat, strong sunlight, and depleted nutrients, these second-flush leaves are thicker and higher in tannins, resulting in stronger bitterness and astringency.

Shading periods are often shortened to around 14 days depending on leaf condition.
Second-flush tea is rarely used for tea ceremony purposes and is more commonly used in confectionery and products combined with dairy or sugar.

Autumn

Matcha is generally not produced from autumn harvests.

★ What Is Not Matcha: Powdered Green Tea

Powdered teas produced without following the above processes are not matcha.

Examples include:

• Powder made from broken sencha leaves generated during sencha processing
• Tea grown without shading in autumn, dried in a tencha furnace and milled (“autumn tencha”)
• Tea harvested in summer or autumn, processed as sencha through kneading and drying, then milled (“moga”)
• Tea shaded for approximately two weeks, processed as sencha (kabusecha), and then milled
  

These products are powdered green teas, not matcha.