Before Fortune, botanists had failed in their attempts to decode the formula for tea. His first collecting trip to China in 1843, for the Royal Horticultural Society, had taken him to the fringes of tea territory as part of his general collecting mandate. At that time he had made an important discovery: Green tea and black tea came from the same plant.
The Linnaean Society had hitherto declared unequivocally that green and black tea were siblings or cousins, closely related but under no circumstances twins. The great [Carolus] Linnaeus, a century before, working from dried samples brought back from China by earlier explorers, concluded that the two were distinct taxa: Thea viridis and Thea bohea. Thea viridis, or green tea, was said to have alternating brown branches and alternating leaves: bright green ovals that were short-stalked, convex, serrated, shiny on both sides, and downy beneath, and with a corolla, or flower, of five to nine unequally sized white petals. Thea bohea, black tea, was described as looking nearly the same—only smaller and somewhat darker.
On his first trip Fortune expected to find identifiable black tea plants in gardens known to produce black tea. Yet he discovered that the tea plants there looked just like the green tea plants in the green tea gardens. Over the course of that first three-year visit, when procuring several tea samples and thoroughly investigating them, he had concluded that any difference between green tea and black was the result of processing alone. His botanical colleagues were slow to agree, requiring more proof.
Black tea is fermented; green tea is not. To make black tea, the leaves are allowed to sit in the sun for an entire day to oxidize and wilt—essentially to spoil a little. After the first twelve hours of stewing, black tea is turned, the liquor is stirred around, and the mixture is left to cure for another twelve hours. This longer curing process develops black tea’s tannins, its strong bitter flavor, and its dark color. Although it is called fermenting, the process of making black tea is technically misnamed. Nothing ferments in a chemical sense; there are no microorganisms breaking down sugars into alcohol and gas. Black tea is, rather, cured or ripened. But the language of wine colors the language of all beverages, and so the label of “fermentation” has stuck to black tea. (Indeed, if tea does ferment and fungus grows, a carcinogenic substance is produced.)
Given that to that point no European botanist had seen tea growing or evaluated it in its living state, the Linnaean Society’s confusion on the subject is understandable. Fortune’s documentary evidence ultimately changed tea’s Linnaean classification. It would soon be known categorically as Thea sinensis, literally tea from China. (Later still it would be reclassified as part of the Camellia family, Camellia sinensis.)
As he made his way through the green tea factory, Fortune took note of something both peculiar and more than a little alarming on the hands of the tea manufacturers. It was the kind of observation that, once reported, would be an invaluable boon to the burgeoning Indian tea experiment, with the power to boost the sales of Indian tea over Chinese. While staring at the workers busy in the final stages of processing, he noticed that their fingers were “quite blue.”
Among the blenders and tasters of the London auction it was generally assumed that the Chinese engaged in all manner of duplicity, inserting twigs and sawdust into their teas to bulk up the loose leaves. It was said that the Chinese were brewing their own breakfast tea, saving the soggy leaves to dry in the sun, and then reselling the recycled product as fresh tea for the gullible “white devils.”
There was no trust in the trade, no faith in the goodwill of the Chinese manufacturers.
But the blue substance on the fingers of the Chinese workmen seemed to Fortune a matter of legitimate concern. What could be the source of this? He and others had long suspected that the Chinese were chemically dyeing tea for the benefit of the foreign market. He was now in a position to prove or disprove the charge.
He watched each step of the processing carefully, saying nothing, making notes, and occasionally asking Wang to put a question to a manager or worker. At one end of the factory the supervisor stood over a white porcelain mortar. In the bowl was a deep blue powder, made finer and finer with each grind of the pestle. The superintendent was in fact preparing iron ferrocyanide, a substance also known as Prussian blue, a pigment used in paints.