Westerners in 1848 were obsessed with tea, and had been drinking it for two centuries--but China had been producing it for two millennia, and no westerner had any idea how it was made, nor were they even allowed into China's interior, where tea was processed. Even the great Linnaeus made basic, glaring errors in his classification of the tea plant, using an incorrect genus and even classifying green tea and black tea as two separate, though related, plants.
This rankled Britain's East India Trading Company to no end. Here they were with a ludicrously popular product, the raw ingredient of which was a stupidly easy-to-grow plant that thrived in the British colony of India. The English had factories. They had cheap Indian labor. They should be making boatloads of money off this stuff. And yet all scientific investigation into how tea was actually made fell flat.
You can't just pick tea leaves and steep them in water. As perfected by the Chinese, tea production was a complex multi-step process involving natural and artificial heat, all kinds of curing, drying, handling, rolling, and sorting. And the Chinese steadfastly refused to share this process. So the East India Trading Company found themselves a spy.
In the wake of the First Opium War between the UK and China, the two nations signed the ridiculously one-sided Treaty of Nanjing in 1842. That ended China's protectionist stance on foreign commerce, and also left the country vulnerable to exactly the kind of industrial spying they were about to fall victim to. In 1848, the East India Trading Company sent one Robert Fortune (one of the more grandly-named spies in history), a Scotsman with a background in horticulture and botany, to travel to China and bring back the secrets of tea.
Fortune, not really a trained spy, nonetheless dressed up in, according to Sarah Rose's For All the Tea In China: How England Stole the World's Favorite Drink and Changed History (excerpted here), "mandarin garb," and visited a tea factory in China's interior. There he discovered the secrets of tea production. Here are some of the things he discovered:
- Green tea and black tea are two different preparations of the same plant.
- Tea leaves were first dried by the sun, then essentially stir-fried in a giant wok, then rolled over bamboo rollers (Fortune compared this to a baker rolling dough), then squeezed to release their green juices. That's just the beginning of the process.
- Workers sorted through the tea, sorting the highest-quality leaves from the lower, and then the "dust."
- The highest-quality teas are made from only the top two leaves and the bud.
- Black tea is cured in the sun for a full day, compared to green tea's one or two hours, then stirred, then cured again.
- The Chinese were poisoning the British.
Armed with this knowledge, Fortu-wait, what?
Turns out, the Chinese assumed that the British only wanted the greenest of green tea, color-wise. The tea that the Chinese drank--the natural color of green tea--was yellow-to-clear, but the British tended to prefer green tea of the brightest green. So the Chinese began dyeing their tea green using a combination of blue and yellow dyes (Fortune began investigating when he noticed that the workers' fingers were stained blue).
The blue dye was a pigment known as Prussian blue--chemically speaking, iron ferrocyanide. The yellow part was actually more troublesome. Instead of a traditional yellow dye, the Chinese factories were using calcium sulfate dehydrate--otherwise known as gypsum, a key ingredient in plaster. Sarah Rose (whose book you should all buy and read) writes:
Gypsum produces hydrogen sulfide gas as it breaks down. While the gas is produced naturally by the body in low doses, in high doses it acts as a broad-spectrum poison, affecting many of the body's systems simultaneously, particularly the nervous system. At lower concentrations gypsum acts as an irritant; it reddens the eyes, inflames the throat, and causes nausea, shortness of breath, and fluid in the lungs. Consumed over the long term it might produce fatigue, memory loss, headaches, irritability, and dizziness. It can even induce miscarriage in women, and failure to thrive in infants and children.
In other words, the Chinese were, albeit mostly through negligence and apathy, poisoning the British sort of significantly. Fortune carefully documented the entire process of both tea processing and poisoning, as well as swiping some samples of both the gypsum and Prussian blue dyes/poisons, and brought them back to England. There, he was hailed as a hero for two reasons: First, he had brought the secret of tea production, and second, he had supplied an airtight reason for British tea-drinkers to buy domestically: British tea would have no such poisons. The Chinese were probably a little more ambivalent about the guy.
[Read an excerpt of Sarah Rose's book at Smithsonian Mag, or buy a copy at Amazon (it's on sale!)]