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Manufacturing Process of Tea

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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

”Aracha” is tea leaves that have been processed until just before they are finished, and they are stored in this state until just before shipment.

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 (oxidization)

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.

Deactivation

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).

Rolling

In this process, pressured kneading equalizes the leaf moisture so that the ingredients get easy to come out.

Fine rolling

This process is to shape the tea leaves by drying with heat and kneading in one direction.

Drying

This process is to further dry the leaves by thoroughly airing hot wind. Here comes Aracha.

Finishing

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. These will be shipped after measuring, checking, and packaging. Finishing enables long storage and enhances the tea flavor.

Sorting/shaping

Aracha is sieved to remove fine stems and sort the leaves by the size. And the following processes such as cutting shape the leaves.

Firing

Drying once again with fire improves the shelf life of the leaves and brings out the tea aroma.

Blending

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.