October 12, 2020
Tea Types | Semi-Oxidized Tea(Oolong Tea)

Tea can be classified into “unoxidized tea,” “semi-oxidized tea,” “oxidized tea,” and “fermented tea” according to the fermentation/oxidation degree. This article guides you through “semi-oxidized tea,” which is least-talked-about among them.

What is semi-oxidized tea?

Semi-oxidized tea is a tea that has been oxidized halfway. “Oolong tea” is representative of it. You can consider it is just in the middle between black tea (oxidized tea) and green tea (unoxidized tea). Oolong tea used to be the only semi-oxidized tea in Japan. However, an unusual semi-oxidized Hōjicha (roasted green tea) produced by some farms is becoming a hot topic these days. In China, the home of tea, semi-oxidized tea is further classified into three types according to the oxidation degree.

Features of semi-oxidized tea’s flavor, aroma, color

Just think about oolong tea, and you will easily understand that semi-oxidized tea has a pleasant scent that is more aromatic than green tea. It is slightly bitter, but has a deep, savory flavor. The refreshing tea is often preferred after a greasy meal with a strong taste, such as meat and Chinese food.

Features of semi-oxidized tea’s ingredients

Tea leaves contain various ingredients. The process of oxidation yields aromatic components to make aromas and pigment components to make colors. Catechin is a component that influences the color of tea. As oxidation turns the liquid color (the color of brewed tea) redder, black tea, an oxidized tea, has a red liquid color. In the case of semi-oxidized tea (oolong tea), which is oxidized only half, the liquid color stays brownish, halfway from green to red.

Features of semi-oxidized tea process

Semi-oxidized tea’s fresh leaves are sun-dried and then spread and roasted in the room for some time. The roasted tea leaves are put in a cloth bag for a while. After kneading and drying, the tea is ready. While oxidized tea is placed in a humid room to be fully oxidized, semi-oxidized tea undergoes roasting to halt oxidization.

Types of semi-oxidized tea

It is uncommon in Japan, but in China the name of semi-oxidized tea varies by oxidation degree.

White tea (bai cha)

White tea is the least oxidized semi-oxidized tea and also called “weakly oxidized tea.” Its manufacturing process does not include “kneading.”

Blue tea (qing cha/oolong tea)

What we know as oolong tea is a member of blue tea. Its oxidation degree varies a lot by type, but blue tea is the most common semi-fermented tea.

Yello tea (huang cha)

Yellow tea has undergone a special heating treatment. After ripening the half-oxidized leaves, the liquid color becomes yellow, as its name suggests.

 

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