How a medicinal plant from south-western China became one of the world's most traded commodities
Few habits feel as domestic as putting the kettle on for a cup of tea, yet the leaf inside the pot has one of the most dramatic histories in global trade. The tea plant, Camellia sinensis, is native to the misty forested hills where south-western China meets northern Burma and Assam. For centuries before it became an everyday beverage, people in these borderlands chewed the bitter green leaves as a medicinal herb or boiled them into a tonic to stay awake during long periods of meditation. Only during the Tang dynasty, between the seventh and tenth centuries, did tea drinking spread across China as a refined social pastime. In the eighth century, the scholar Lu Yu wrote the Chajing, or Classic of Tea, describing how freshly picked leaves were steamed, crushed in a mortar and pressed into solid bricks that could be dried over charcoal and carried for thousands of kilometres without spoiling.
The way tea was prepared continued to evolve. Under the Song dynasty, compressed tea was ground in stone mills into a fine green powder and whisked in bowls with hot water to create a pale, frothy foam. Buddhist monks who travelled from Japan to study in Chinese monasteries brought both tea seeds and this whisked preparation home with them, laying the foundations of the Japanese tea ceremony. In China itself, however, tastes shifted decisively at the end of the fourteenth century. The founder of the Ming dynasty, Emperor Hongwu, abolished the imperial tribute of compressed tea bricks in 1391, decreeing that tea should instead be presented in the form of loose leaves. Steeped directly in hot water inside clay or porcelain teapots, whole leaves released a clearer, more fragrant infusion, establishing the method of brewing that most of the world still follows.
Long before a single chest of tea reached Europe by sea, vast quantities moved overland across Asia. Along the treacherous mountain trails of the Tea Horse Road, porters and mule caravans carried heavy loads of compressed tea from Sichuan and Yunnan up onto the Tibetan plateau, trading them for the sturdy warhorses that Chinese dynasties needed to defend their northern frontiers. Maritime trade with Western Europe began much later. Although Portuguese priests and travellers wrote brief accounts of Chinese tea in the sixteenth century, it was the Dutch East India Company that shipped the first commercial cargoes to Amsterdam in the early seventeenth century. At first, tea was sold by apothecaries as a costly tonic rather than a daily drink, and only wealthy merchant families could afford the silver canisters in which the dried leaves were kept under lock and key.
In Britain, tea remained a curiosity in the 1650s, advertised in London coffee houses alongside coffee and hot chocolate. Its social standing rose sharply after 1662, when the Portuguese princess Catherine of Braganza married King Charles II. Having grown up in Lisbon, where tea drinking was already well established among the nobility thanks to Portugal's eastern trade routes, the new queen made the beverage fashionable at the English court. Even so, steep customs duties kept legal tea far beyond the pockets of ordinary working people for another hundred years. High taxation created a thriving black market: armed smuggling gangs landed untaxed tea in quiet coves around the British coast, while dishonest shopkeepers stretched their stocks by mixing genuine tea with re-dried used leaves, ash and willow leaves.
The turning point came with the Commutation Act of 1784, which slashed the tax on tea from more than 100 per cent to just 12.5 per cent. Overnight, smuggling ceased to be profitable, prices fell, and tea became a staple of the British diet across every social class. Paired with cheap sugar imported from plantations in the Caribbean, hot sweet tea gave agricultural labourers and factory workers a quick, comforting source of calories during long, cold shifts. Yet Britain's unquenchable thirst for tea created a severe financial headache. China was still the world's sole commercial supplier, and Chinese merchants cared little for British woollens or metalwork, insisting on being paid in silver bullion. Year after year, silver drained out of London to pay for dried leaves.
Determined to break China's monopoly, the British East India Company began searching for places to grow tea within its own territories. In the 1820s, British travellers confirmed that an indigenous variety of the tea plant grew wild in the warm, humid forests of Assam in north-eastern India, where local Singpho communities already brewed it. Botanists in London, however, initially doubted that this coarse-leaved wild plant could produce a drink to rival delicate Chinese varieties. To hedge its bets, the company also hired the Scottish botanist Robert Fortune in the late 1840s to travel into China's famous tea-growing provinces. Disguised in local dress, Fortune smuggled out thousands of tea seedlings and seeds in portable glass cases, along with experienced Chinese tea makers who knew how to roast and roll the leaves.
Ironically, most of Fortune's imported Chinese plants struggled in the Indian climate, whereas the native Assam variety thrived once forests were cleared for large-scale plantations. British engineers soon introduced coal-fired driers and mechanical rolling machines, turning tea production from a painstaking village craft into a fast industrial process. A further boost came in the 1870s, when a devastating fungal disease known as coffee rust wiped out the coffee estates of Ceylon, modern-day Sri Lanka. Ruined planters tore up their dying coffee bushes and replanted the hillsides with Assam hybrid tea. By the close of the nineteenth century, South Asian plantations had overtaken China as Britain's chief suppliers, and brisk, dark black tea had largely replaced the lighter green teas that Europeans had first tasted two centuries earlier.