Tea Ingredients | Aroma Compounds

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The aroma compounds contained in tea can be described as the compounds that create a variety of aromas such as aromas of roasted tea leaves and young leaves.

Surprisingly, there are more than 300 different aroma compounds like these in tea.

This time, we are going to introduce the major aroma compounds and how each compound creates aromas.

Tea aroma is subtle and complex

The “tea aroma” varies from tea to tea, and there exists a wide range of aromas, from savory and young leafy aromas to sweet and floral aromas. These aromas are created by compounds called “aroma compounds”.

Tea is a beverage rich in aroma components, with green tea containing about 200 aroma components and black tea and oolong tea containing more than 600 aroma components. The delicate and complex aroma of tea is created by the combination of various aroma components.

Difference between Black Tea & Oolong Tea and Green Tea

Black tea, oolong tea and green tea are all produced from the same tea leaves. However, each one of these teas has their own characteristic aromas as if they are not from the same tea leaves. This is because each tea is produced in different processes that create different aroma compounds.

Now, let’s see the 3 different tea-producing processes and the aromas created in those 3.

Green tea

At the beginning of producing green tea, there is a process called “sassei” that is to steam and heat freshly picked tea leaves. This process deactivates enzymatic fermentation (oxidization) in the leaves from producing aroma compounds, which keeps refreshing aromas of tea leaves.

But, this doesn’t mean that green tea has few aroma compounds: even though the fermentation stops, there are still more than 200 aroma compounds contained in green tea.

Black tea / Oolong tea

Black tea and oolong tea leaves would first be withered, instead of the heating process like the green tea’s. When tea leaves are not heated at the beginning, oxidation would get enhanced to produce a variety of aroma compounds.

As a result, black tea / oolong tea contains about 600 aroma compounds, while green tea contains about 200.

This is how floral and fruity aromas are produced in tea leaves to make the flavor of black tea / oolong tea. In other words, the types and volume of aroma compounds produced from the same tea leaves would vary according to the time length of oxidation.

Major aroma compounds

Now, let’s see the major aroma compounds contained in tea.


Linalool is an aroma compound with the light and refreshing odor like lily of the valley. It has effects of antibacterial, antivirus and immunity booster.


Geraniol is an aroma compound with the rose-like odor. It is used to produce the artificial citrus flavor and vitamin E and A supplement.

Leaf alcohol

Leaf alcohol is an aroma compound with the refreshing odor of young leaves. It is used to produce artificial flower essential oils and food flavors.


Cis-jasmon is an aroma compound with a sweet and thick odor like jasmine and gardenia. It is mainly contained in black tea and used to produce fruity or floral compounded fragrances.

Dimethyl sulfide

Dimethyl sulfide is an aroma compound with the odor of lavor(green seaweed). It is contained in nori seaweed and wasabi, and it can cause bad smells when using a big amount. However, since only a small amount is contained and blended with other aroma compounds in tea, it only plays a role to create refreshing aromas.

Dimethyl sulfide is a component produced by covered cultivation, and is commonly found in high-end teas such as kabusecha, gyokuro, and matcha. Because of the way it is cultivated, it is sometimes referred to as “Ooi-ka(covered aroma)”.


Indole is an aroma compound with a grassy, bitter and heavy odor. It is also contained in jasmine oil and coal-tar.

Indole itself can cause bad smells like dimethyl sulfide, but it would have the floral odor when low-concentrated.


Pyrazine is an aroma compound with a roasting odor created by heating.

Particularly, the roasting aroma of Japanese tea comes from pyrazine.