Black tea and green tea come from the same plant species.

Tea makers control enzymatic oxidation, a set of reactions that changes leaf compounds after harvesting and handling. Black tea is allowed much more oxidation than green tea.

Heating leaves early in green tea production limits the enzymes responsible for oxidation. Steaming and pan firing are different ways to perform this crucial processing step.

Cultivar, climate, season and leaf selection also matter. Sharing a species does not mean that every tea begins with genetically identical leaves or identical growing conditions.

A tea plantation is not normally divided into one species for black tea and an unrelated one for green tea. Camellia sinensis supplies both. It is an evergreen plant in Theaceae, and growers manage its leafy growth for repeated harvests. Kew describes tea production as involving picked leaves that may be baked, steamed, rolled and dried to produce different styles.

Fresh leaves contain enzymes and the compounds those enzymes can act on. Withering reduces moisture and makes leaves more pliable. Rolling or other handling disrupts cells, allowing components to interact more readily in the presence of oxygen. During black tea manufacture, that interaction is encouraged before drying ends the desired sequence. The result is a changed chemical mixture, not just a leaf that has become dry.

Green tea follows a different timetable. Producers apply heat early to reduce enzymatic activity, helping preserve a different balance of leaf compounds. Japanese styles often use steaming, while many Chinese styles use pan heating. Those are broad traditions rather than universal rules. Shaping and final drying still influence appearance, handling and flavor after the crucial oxidation-limiting step.

Oolong provides another illustration of processing control because its manufacture permits an intermediate extent of oxidation. White teas undergo comparatively limited handling, though some oxidation can occur. These categories are useful guides rather than precise chemical percentages stamped onto every leaf. Two teas within a single category can taste strikingly different because their plants, environments and manufacturing details differ.

Older descriptions sometimes call the oxidation of black tea “fermentation.” For ordinary black tea, that wording can mislead readers into imagining the microbial process used to make yogurt. Enzymatic oxidation is the main distinction here. Some other tea categories do involve important microbial transformations, so the correct explanation depends on the tea rather than on a blanket claim that fermentation never occurs.

Brewing is a separate stage from manufacture. Water temperature, leaf quantity and steeping time affect what reaches the cup. Both black and green tea naturally contain caffeine, with the amount in a serving influenced by the product and preparation. Peppermint and chamomile infusions may share the everyday word “tea,” but they come from other plants and do not become Camellia sinensis through similar brewing.

Tea and coffee illustrate contrasting beverage ingredients: leaves in one case and seeds in the other. Their processing histories also matter before brewing begins. Comparing the harvested parts keeps the explanation concrete, rather than treating every dark hot drink as the product of a similar crop or manufacturing sequence.