Every tea begins with Camellia sinensis. The Chinese classification recognises six broad classes: green, yellow, white, oolong, red and dark tea. In common English usage, red tea is usually called black tea.
The classes describe how the leaf is made. Variety, garden, season and craft create enormous range within each one, so a class is an orientation rather than a promise of one flavour.
Green tea
For green tea, heat comes early. Steaming or pan-firing fixes the fresh leaf before extensive oxidation develops. The leaf is then shaped and dried. Japanese steamed greens and Chinese pan-fired greens reveal how much the choice of heat can shape the finished tea.
Green tea therefore carries real craft and change. Its defining feature is the early fixing step, not an absence of processing.
Yellow tea
Yellow tea begins close to green tea, then receives a warm, damp resting step called men huang. The fixed leaf is wrapped or covered so that heat and moisture continue to alter it gently.
This extra stage defines the class. It is distinct from the extensive oxidation used for red tea and from the fermentation of dark tea.
White tea
White tea is chiefly withered and dried, with little rolling and no deliberate early fixing. During the long wither, moisture leaves the leaf and gradual change continues.
Its handling may be spare, yet the leaf remains active throughout the wither. White tea is best understood through this sequence rather than through claims that it is untouched.
Oolong
Oolong occupies the widest field. The leaves are withered and repeatedly moved or bruised to encourage partial oxidation. The maker then applies heat to fix the leaf at the chosen point. Shaping and roasting may follow.
The degree of oxidation varies greatly across oolong styles. A lightly oxidised rolled oolong and a deeply roasted strip oolong can appear very far apart while belonging to the same class.
Red tea, commonly called black tea
Red tea is the primary Chinese category term, hong cha. Common English usage calls the same class black tea. After withering and rolling, the leaf undergoes extensive oxidation before drying.
The two names look at different parts of the tea. The Chinese term points to the colour of the liquor, while the English term points to the darkened leaf. Here, red tea names the category first, with black tea offered as the familiar English label.
Dark tea
Dark tea, hei cha, is defined by microbial fermentation. Some forms are piled while warm and moist. Others continue to change through storage. Ripe puer belongs within this broad field, while raw puer follows its own slower course.
Red tea and dark tea are therefore separate classes. Red tea is extensively oxidised during manufacture. Dark tea receives fermentation involving living microorganisms.
Reading a tea through its making
The six classes offer a map of decisions: when the leaf is heated, how it is moved, whether it is wrapped, how far oxidation proceeds, whether fermentation enters, and how drying or roasting closes the work.
What a class can reveal
A class names the broad path of making. It helps distinguish an early-fixed green from a partly oxidised oolong, or an extensively oxidised red tea from a fermented dark tea. That knowledge makes the dry leaf and the spent leaf easier to read. Shape, colour and compression become traces of craft rather than decoration.
A class also has limits. It cannot establish the quality of the harvest, the care of the maker or the character of a particular sitting. Green tea contains many traditions. Oolong holds an especially wide range. Dark tea includes processes and storage histories that deserve their own names.
At the table, the six-class map is a beginning. The label offers the class, origin and maker. The bowl then reveals the particular tea through colour, aroma, texture and the way successive infusions change. Classification keeps the field coherent while leaving the individual leaf intact.
Once that map is clear, a tea label becomes more useful. The class gives the first orientation. Place, cultivar, harvest, maker and preparation reveal the rest.