The species explains less. Green tea and black tea can begin on the same plant, yet emerge from processing with different colors, aromas and tastes because their leaves follow different chemical paths after picking. The distinction is manufactured. Not in the sense of something artificial, but through decisions about heat, handling and exposure to oxygen that redirect the leaf's chemistry.
Heat makes the difference. In green tea production, steaming or pan heating early in processing deactivates enzymes, including polyphenol oxidase, which would otherwise help drive oxidation when leaf tissues are damaged. Timing changes the result. By limiting that reaction, producers retain more of the original catechins, a group of compounds that contribute bitterness and astringency, while preserving qualities often described as grassy or vegetal. Black tea takes longer. Its leaves are typically withered, rolled or otherwise disrupted, then allowed to oxidize before drying stops the reactions and reduces moisture for storage.
Color tells only part. During black tea processing, oxidation converts some catechins into other compounds, contributing to a darker infusion and changing its taste, though variety, growing conditions and brewing still influence the cup. The labels conceal variation. Neither category guarantees a particular caffeine level or a fixed flavor, and black tea's oxidation should not be confused with microbial fermentation, even though that word sometimes appears in descriptions of its manufacture. Origin remains only part. Between the living leaf and the finished drink lies a brief interval when a producer decides which changes to permit and which to stop.
