Steaming vs fermenting vs Roasting for Japanese tea

Tea leaves after being plucked from the plant are sent for processing. The processing involves a bunch of methods through which tea leaves are transformed into dried and preserved leaves for later brewing. The tea from the same plant, Camellia Sinensis are differentiated based on the process they undergo, which involves oxidation of leaves of different levels, formation, and drying.

The first step for any kind of tea leaves is either steaming, fermenting, or roasting, depending on the kind. The steaming process is fixed for green tea, black tea leaves go through the fermentation process, and roasting is dedicated to oolong tea leaves. All these have the same purpose, to inactivate enzymes that speed up the decaying process and change the components. However, each tea has its method because it also preserves the desired taste and color in each tea.

Steaming

The steaming process is used crude tea leaves because it eliminates the grassy leaves smell, produces green tea aroma, inactivates enzymes in leaves, and makes the leaves easy to use later. Just after picking, green tea leaves are sent to the factory for processing. They are steamed in high heat immediately, which helps in activating enzymes and enhancing the aroma.

Enzymes, if still present in tea leaves, start to change the component and oxidize the catechins with oxidized polyphenol. Catechins are an essential ingredient in green tea as it has numerous health benefits, and if destroyed, it does not give benefits but disadvantages. It works as an antioxidant in your blood and gets rid of oxidant radicals. Therefore, steaming is important to keep the catechins in tea and get benefits.

Most of the time, the steaming process depends on the tea plant’s growing conditions such as environment and elevation. Different kinds of green tea have a period of steaming. Some are steamed for half a minute and some to a full minute or more to preserve maximum taste and enhance qualities.

The more it is steamed, the easier it is for leaves membranes to break in later processes and release flavor. Shorter steamed has a lighter color and a higher estrogen level. At the same time, steamed leaves have a more greenish color, low astringency level, and smooth liquid. Some green teas are steamed twice for the better effect and different flavors.

Fermenting

Black tea leaves are not steamed therefore hold distinct qualities that are obtained with fermentation. It is also called fermented tea because it goes through fermentation to stop enzyme activities. Black tea leaves have many catechins which are oxidized and leave an astringent taste. Oxidize from catechins gives the taste and theafrabin; another oxide gives the color to the tea due to fermentation.

Fermentation, in the case of black tea, involves enzymatic oxidation when leaves are dried in the presence of atmospheric oxygen. The heat and moisture evaporate from leaves, and the dry and dark tea leaves remain. Leaves are then oxidized under controlled environment conditions. It can be done on batches or conveyor belts with proper airflow and temperature control.

The level of oxidation has a prominent effect on black tea, and each kind of tea has different levels to get the desired characteristics. The tea when brewed has a darker color and is rich with oxidation and such qualities depend on the fermentation period. Longer time results in a darker and more robust flavor.

Roasting

There are many tea kinds that do not have the above methods to inactivate enzymes but instead are roasted on an iron plate to get the same result. Roasting is also known as a pan-fried method. You fry tea leaves on a pan with limited heat until they emit aroma and look brownish. Oolong tea and Hojicha green tea are commonly roasted during the processing.

Roasting can be divided into two categories, during processing or after processing. If leaves are roasted during the processing, water reduces from them and results in storage for an extended period. It also removes the raw taste due to heat and thus makes it more suitable to use. Roasting also helps in stopping oxidation, just like other above methods help.

The length and intensity of roasting affect the taste and aroma of the tea. Light roasted will have a faint taste and whereas strongly roasted tea leaves give rich aroma and flavor. Heavy roasting also helps in reducing caffeine levels, which comes beneficial in many cases.

The roasting after the processing has many reasons and foremost is to preserve it for a longer time. It is a great process to make your tea leaves refreshed and prevent decay. Roasting also enhances the flavor to the maximum and gives a new taste.

Here are examples of roasted tea we carry:

• ShizuokaTea – Houjicha – Roasted Green Tea Leaves

Steaming vs Fermenting vs Roasting — Frequently Asked Questions

What are the three main tea processing methods? How does steaming work for Japanese green tea? How does fermenting (oxidation) work for black tea? How does roasting work for tea? Why do these different methods exist?

What are the three main tea processing methods?

Tea leaves from the same Camellia sinensis plant are differentiated mainly by the first processing step they undergo: steaming, fermenting (oxidation), or roasting. Steaming is the method used for green tea — including Japanese green tea. Fermenting is used for black tea. Roasting is used for oolong tea and, in a separate step, for Hojicha. Each method inactivates the enzymes in fresh tea leaves to halt natural decay, but each preserves different flavors, colors, and chemical profiles in the finished leaf.

What is Sencha and what tea is considered Sencha

Read more

What is Hojicha (ほうじ茶)

Read more

How does steaming work for Japanese green tea?

Just after harvest, green tea leaves are sent immediately to the factory for steaming at high heat. The steaming inactivates the enzymes that would otherwise oxidize the catechins in the leaves. Without this step, the leaves would oxidize and lose their distinctive green color, fresh aroma, and antioxidant benefits. Steaming also breaks down the grassy raw-leaf smell and produces the clean vegetal aroma characteristic of Japanese green tea. Different steaming durations produce different styles — light (Asamushi), normal (Futsumushi), or deep (Fukamushi).

Premium Sencha - New Crop (Shincha) From $19.00 /

What is Asamushi Cha（浅蒸し茶）

Read more

What is Fukamushi Cha?

Read more

How does fermenting (oxidation) work for black tea?

Black tea leaves are not steamed — instead, they go through a controlled fermentation process. Strictly speaking, the process is enzymatic oxidation rather than microbial fermentation: the leaves are dried in the presence of atmospheric oxygen, with controlled heat and moisture. The leaves' catechins oxidize into theaflavins and thearubigins, which produce the characteristic darker color and robust astringent flavor of black tea. Longer oxidation produces darker, more robust tea; the duration of oxidation is the main control variable in black tea processing.

How does roasting work for tea?

Roasting (sometimes called the pan-fried method) inactivates the enzymes in tea leaves using direct heat rather than steam or oxidation. The leaves are heated on a hot pan or roller drum until they emit a toasted aroma and develop a brownish color. Oolong tea is roasted during initial processing. Hojicha is unique: it is first steamed (like other Japanese green teas) and then roasted as a second step — combining both methods to produce its distinctive smoky character.

What is Hojicha (ほうじ茶)

Read more

Why do these different methods exist?

Each processing method preserves a different set of qualities. Steaming preserves the highest catechin content and the freshest, most vegetal flavor — ideal for green teas where freshness and antioxidants are central. Fermenting trades catechin preservation for a deeper, more robust flavor and a longer shelf life — ideal for black teas. Roasting reduces caffeine and astringency while developing a toasted, nuttier flavor — ideal for evening drinking, child-friendly teas, and tea pairings with food. The same Camellia sinensis leaf can yield wildly different drinks depending on the method.

Related products

4 reviews

Premium Sencha - New Crop (Shincha)

$79.00 /

Premium Deep Steamed Sencha (Fukamushi-cha) is crafted from select early-spring tea leaves that are steamed longer than standard Sencha, creating a deep green infusion with a rich, velvety body and gentle sweetness.

View Product

Premium Sencha

The lovely fragrance of the Premium Sencha tea leaves in the package is very pleasing. The light clear liquid from the first infusion provides a very well balanced wholesome flavor with a slight astringency along with floral hints. The second infusion tastes much the same as the first but is a little bit sweeter. Premium Sencha is a distinctive tea

View Product

Organic Houjicha

Houjicha ほうじ茶(AKA hojicha) is good quality Japanese green tea that is roasted in the final stage of its preparation. In less skilled hands than our artisan supplier, Houjucha often has a burnt odor and taste. However, the brown-colored liquid from the first infusion has a very mild roasted flavor and is exquisite tasting. The gentle natural sweetness and tangy aftertaste are very satisfying.

View Product