Part 3 - Processing Matcha: From Fresh Leaves to Tencha

Tea farmers immediately transport the freshly plucked leaves to a crude tea factory, where they are processed into “crude tea.”

Crude tea is made by steaming and then drying fresh leaves to significantly reduce their moisture content, bringing them to a condition suitable for distribution. This constitutes the primary processing stage in producing tencha, the raw material of matcha.

The biggest difference between crude tea processing for tencha and for sencha lies in the kneading process: tencha are not kneaded at all. As a result, the leaves retain their original shape when finished.

Steaming Process

After harvesting, the tea farmer immediately brings the fresh leaves to the crude tea factory, where the steaming process begins.

The steaming process involves exposing the fresh leaves to high-temperature steam for a short time. Steaming enhances the vivid green color and brings out the unique “shaded leaf aroma.” It also serves to deactivate oxidative enzymes that promote fermentation.

The steaming must take place within 24 hours of harvesting; if not done properly, the leaves begin to ferment and brown.

Crude tea factories with high technical capability are in high demand, so farmers sometimes have to wait for their turn to begin steaming. In such cases, the fresh leaves are temporarily stored in a fresh-leaf management unit called a “pit,” which is designed to slow oxidation by blowing cool air through the leaves.

The steaming operation itself is the same for tencha and sencha, but the steaming time differs. For sencha, known as “the standard ‘normal steaming’ method” the time is about 30 to 45 seconds. For tencha, it is slightly shorter, around 20 to 30 seconds. This shorter steaming time is because the leaves cultivated under shading cultivation are softer and conduct heat more readily than those grown in open sunlight.

Tea Leaf Spreader

After steaming, the leaves are transferred to a specialized tencha machine called a “tea leaf spreader.” The purpose is to remove excess surface moisture and evenly spreads them to orevent overlapping.

Using air pressure from a blower, the steamed leaves are lifted inside a breathable chamber called the “air-lifting net” and allowed to fall naturally. Repeatedly lifting and dropping the leaves both cools them and dries the surface moisture, ensuring the leaves remain well-separated.

The leaves are then conveyed to the lower conveyor of a tencha-dedicated drying furnace, the “tencha furnace.”

Tencha Furnace (Drying Process)

The steamed leaves coming from the tea leaf spreader are dried in a tencha-dedicated brick furnace called a “tencha furnace,” using hot air and radiant heat. Here, the leaves also acquire their distinctive toasty aroma, known as “fire aroma.”

At the bottom of the tencha furnace is the firebox, and three conveyer belts are located above it. The steamed leaves are first placed on the lowest belt, closest to the heat source, and undergo rough drying at 175–180°C. The leaves are rapidly dried by radiant heat, and the generated steam naturally vents outside.

The leaves are then lifted by air pressure from the lower to the upper belt, and finally to the middle belt. The entire process in the tencha furnace takes about 30 minutes.

This stage is crucial for removing the grassy odor naturally present in the fresh leaves and imparting the characteristic “fire aroma” unique to furnace drying. Since moisture content differs greatly between leaves and stems, they are separated after drying and then subjected to final drying individually.

Crude tencha have a dried, leaf-shaped material, as shown in the photo.

This is how crude tencha are produced.

If the steaming time is too short, a grassy odor remains; if too long, the “shaded leaf aroma” is lost. The “fire aroma” generated in the tencha furnace is extremely important. Over-drying causes the color to darken and the aroma to dissipate, while under-drying leaves a grassy note.

Each factory possesses its own technical know-how, and the skill level differs among crude tencha factory. Tea farmers entrust their carefully cultivated leaves to factories with advanced technical expertise to ensure high-quality crude tencha production. For this reason, demand concentrates in highly reputed tencha processing factories.

When fresh leaves are processed into crude tea, their weight is reduced to about one-fifth. In other words, 100 kg of fresh leaves become about 20 kg of crude tencha—a result of the significant loss of water content.

Moga Tea

In addition to the crude tencha described above, there exists a simplified type called “moga tea,” which is made without using a tencha furnace.

While teas such as sencha and gyokuro, which are kneaded during processing, are called “momi-cha” (kneaded tea), “moga tea” is made using the same processing line as momi-cha.

For sencha and gyokuro, after steaming and cooling, the process proceeds through (1) rough rolling → (2) kneading → (3) intermediate rolling → (4) fine rolling.

In contrast, “moga tea” is made by omitting step (4): after (1), (2), and (3), the leaves are dried in a dryer without shaping them into fine needles.

In this way, tencha-like material can be produced in sencha or gyokuro producing regions using existing “momi-cha” machinery without a tencha furnace.

However, whether this product should be called tencha is still a matter of debate.

Distribution of Crude Tea

The tea farmer’s work in producing crude tencha ends here.

Crude tea is then transferred to tea manufacturers either through:

(1) Direct transactions between tea farmers and tea manufacturers (“iritsuke”), or

(2) Auctions conducted through agricultural cooperatives (JA) and traded to tea manufacturers.

In Kyoto, a well-known Japanese tea producing region, crude tea used to be traded mainly through direct transactions (“iritsuke”) before the establishment of the JA auction system, but nowadays, auctions are more common.