Over the last month (or rather, several months) we’ve been busy finalising the draft for our forthcoming book, Empire of Tea: the Asian Leaf that Conquered the World. As part of that process we audited and refined the core strands of history and argument that run through the text. One the most fascinating facets of tea’s story in Britain, as far as I’m concerned, is the fact that – alongside Caribbean sugar – it was really the first international commodity to saturate a mass market. I’m aware, of course, that plenty of other goods – pepper, coffee, chocolate, silks – were consumed far and wide in Britain at even earlier junctures. But until tea worked its magic in the eighteenth century, permeating more-or-less every single household, nothing reached all the way down the social scale other than essential domestic products (such as flour and wool).
Commentators during the period developed a trickle-down metaphor to describe this process. ‘The consumption of Tea in this Kingdom is […] not confin’d principally to the Rich & middle Classes of the People as heretofore’, a paper prepared for the Commissioners of Excise had explained in the late 1770s; rather ‘it has found an entrance into every Cottage’. A couple of decades later, the East India Company clerk (and Fellow of the Royal Society) Robert Wissett explained that tea ‘may be literally said to have descended from the palace to the cottage, and from a fashionable and expensive luxury, has been converted into an essential comfort, if not an absolute necessary of life’. As Wissett implies – and others pondered puzzlingly – the strangeness of this development was that a non-nutritional cash crop, grown by Chinese peasants on small-holdings, was being shipped halfway round the world for retail to British labourers whose disposable incomes and standards of living were very low indeed. Even stranger was that this enterprise was such a profitable and enduring success.
Eighteenth-century tea was an economic trailblazer. Globalised capitalism is now extremely adept at encountering, appropriating, commodifying, and incorporating new objects and ideas. Indeed, this is what drives it: think iPads, organic artichokes, sub-prime mortgages. Such complex and learned behaviour does not come naturally. Britain’s encounter with tea – its appropriation, commodification, and incorporation of the beverage within its daily life – was a signal stage in the sequence via which capitalism developed its armoury of tropes and tactics for bringing to market from around the world the latest must-have products that we never knew we needed.
In the process of discussing and writing the book, Markman Ellis coined the term ‘luxo-necessity’ to describe tea’s social and economic significance. Elsewhere, Julie Fromer has written of tea’s nineteenth-century cultural meanings as the tale of a ‘necessary luxury’. Both formulations cleverly capture Wissett’s sense of bewilderment when comprehending how ‘from a fashionable and expensive luxury’ tea had been ‘converted into an essential comfort’ – but not ‘an absolute necessary’ – of British ‘life’. Comprising little more than boiled water, tea cannot possibly be conceived as a physical requisite for sustaining human existence. But its powerful permeation of individual diets and collective habits has transformed it into a necessity in other ways: psychologically, socially, economically, culturally.
 London, National Archives, Treasury Papers, T 1/542, fol. 229r.
 Wissett, sig. [C4r].