Camellia sinensis, the evergreen shrub or small tree belonging to the Theaceae family, is the fundamental source of the world’s favorite beverage – tea. Native to East Asia, its name, sinensis, denotes its origin, meaning “from China” in Latin. With leaves, leaf buds, and stems contributing to tea production, this plant has become a cornerstone of global cultivation and consumption.
Two major varieties of Camellia sinensis dominate tea production: the small-leaved Chinese variety (C. s. sinensis) and the large-leaved Assamese variety (C. s. assamica). These varieties are primarily associated with the production of black tea. The leaves from these varieties undergo diverse processing methods, resulting in a spectrum of tea types, including white, yellow, green, oolong, dark (pu-erh), and black tea. The degree of oxidation during processing determines the distinct characteristics of each tea variety.
Tea plants are believed to have originated in the borderlands of north Burma and southwestern China. While native to East Asia, the cultivation of Camellia sinensis has expanded globally, with tropical and subtropical regions being the preferred growing environments. Cultivated as an evergreen shrub or small tree, it is often trimmed to a height below 2 meters when grown for its leaves. The plant thrives in rich, moist soil with at least 127 cm (50 in) of annual rainfall and can endure climates in hardiness zones 7–9.
Camellia sinensis displays distinct characteristics, from its yellow-white flowers with seven or eight petals to its 4–15 cm (1.6–5.9 in) long and 2–5 cm (0.79–1.97 in) broad leaves. Fresh leaves contain approximately 4% caffeine, accompanied by related compounds like theobromine. Harvesting involves selecting the young, light-green leaves, preferably when they have short, white hairs on the underside. This hand-picking process, focused on the tip (bud) and the first two to three leaves, occurs every one to two weeks.
Tea cultivation requires specific environmental conditions. While Camellia sinensis can thrive in tropical and subtropical climates, it is also cultivated in regions with varying climates, ranging from the equator to as far north as Cornwall and Scotland on the UK mainland. High-quality teas are often grown at elevations up to 2,200 m (7,200 ft), where the plants grow more slowly, enhancing flavor.
A notable aspect of Camellia sinensis is its production of caffeine, functioning as a secondary metabolite with natural pesticide properties. This caffeine content acts as a defense mechanism against herbivorous insects, capable of paralyzing and killing those feeding on the plant. The biosynthesis of caffeine occurs in young tea leaves and is regulated by various enzymes.
Camellia sinensis stands as a botanical marvel, providing
the raw materials for an array of teas enjoyed worldwide. From its historical
origins to its global cultivation and unique processing methods, this plant’s
role in tea production is grounded in scientific principles. Understanding the
intricacies of Camellia sinensis enhances our appreciation for the complexities
that culminate in a simple cup of tea.
