How Matcha Is Made: From Leaf to Powder

The process of turning a tea leaf into the bright green powder you whisk into a bowl of matcha is more involved and more carefully managed than the production of most other teas. Understanding that process helps explain why good matcha looks and tastes the way it does, why the grade and quality vary, and why genuine matcha is priced as it is.

The shading period

Several weeks before harvest, typically three to four weeks, the tea plants designated for matcha production are covered with shade cloth or bamboo screens that block most of the direct sunlight. This shading period is the defining step that separates matcha production from ordinary green tea. In full sunlight, the tea plant would convert most of the L-theanine in its leaves to catechins. 

In shade, this conversion is suppressed, and L-theanine accumulates. At the same time, the plant ramps up chlorophyll production in an attempt to capture whatever light is available. The result is leaves that are higher in L-theanine, which gives ceremonial matcha its natural sweetness and the calming effect it is known for, and dramatically higher in chlorophyll, which gives matcha its vivid, almost luminous green colour.

Harvest

The first harvest of the year, in spring, produces the highest quality matcha leaves. These first-flush leaves are the youngest and most tender, having accumulated the most L-theanine and chlorophyll during the shading period. They are also the most expensive because they require the most careful labour to harvest correctly. Later harvests produce leaves for lower grades of matcha and other tea products.

Steaming and drying

Immediately after harvest, the leaves are briefly steamed. This halts the enzymatic activity that would otherwise begin oxidising the leaf compounds and turning them brown, the same process that makes black tea black. Green tea and matcha are both made from unoxidised leaves, and the steaming step is what preserves the green colour and the active compounds. After steaming, the leaves are dried at carefully controlled temperatures, again to prevent oxidation and preserve quality.

Sorting and de-stemming

The dried leaf material, at this stage called aracha, is sorted to remove stems, veins, and any lower-quality leaf material. The stems and veins are woody and would make the powder coarse and less smooth. Only the pure, flat leaf material, called tencha at this stage, goes forward to milling. This sorting process is time-consuming and contributes significantly to the cost of ceremonial grade matcha, which uses only the most carefully selected tencha.

Stone milling

The tencha is fed very slowly through granite stone mills that grind it into matcha powder. The stone mills are kept at low speeds to prevent friction heat from degrading the delicate compounds in the leaf. The milling is slow by design: a single granite mill might produce only thirty to forty grams of finished matcha per hour. The fineness of the resulting powder, measured in micrometres, is what gives matcha its characteristic silky texture and its ability to dissolve in water when whisked.

Common questions

Why is matcha more expensive than regular green tea?  The shading process, first-flush harvest timing, careful sorting, and slow stone milling all add labour and time to production that steeped green tea does not require.

Can the same tea plants be used for other teas?  Yes. The same Camellia sinensis plants produce different tea products depending on how they are grown, harvested, and processed. The shading and milling are what make matcha different.

Does the milling process affect quality?  Yes. Matcha milled too quickly generates heat that degrades the active compounds and affects colour and flavour. Slow, cool milling preserves quality.

For more on the plant behind the powder, see the matcha plant guide, which covers the botany and growing conditions that produce high quality matcha.