The first English recipes for iced chocolate desserts, nearly 350 years old, have been uncovered by a lecturer at the University of Leicester – just in time for the last of the summery weather.

But it seems that in the 17th century, these chilly treats were believed to be as dangerous as they were delightful.

Dr Kate Loveman of the University's School of English has published a new paper, The Introduction of Chocolate into England: Retailers, Researchers, and Consumers, 1640–1730, in the Journal of Social History exploring the early history of chocolate in England.

She has found the first English recipes for iced chocolate treats, collected by the Earl of Sandwich in 1668 – some hundred years before his great, great grandson allegedly invented the sandwich.

The Earl's own recipe reads: "Prepare the chocolatti [to make a drink]… and Then Putt the vessell that hath the Chocolatti in it, into a Jaraffa [i.e. a carafe] of snow stirred together with some salt, & shaike the snow together sometyme & it will putt the Chocolatti into tender Curdled Ice & soe eate it with spoons."

Dr Loveman said: "It's not chocolate ice-cream, but more like a very solid and very dark version of the iced chocolate drinks you get in coffee shops today. Freezing food required cutting-edge technology in seventeenth-century England, so these ices were seen as great luxuries."

"Chocolate was first advertised in England around 1640 as an exotic drink made from cacao beans. In the 1660s, when the Earl of Sandwich collected his recipes, chocolate often came with advice about safe consumption. One physician cautioned that the ingredients in hot chocolate could cause insomnia, excess mucus, or haemorrhoids. People worried that iced chocolate in particular was 'unwholesome' and could damage the stomach, heart, and lungs.

"There were ways round this, however. Sandwich thought the best way to ward off the dangers of eating frozen chocolate was to 'Drinke Hott chocolatti ¼ of an houre after' it. In other words, chocoholics are not new.

"I tried out the freezing method using snow – and lived to tell the tale, despite not following Sandwich's advice."

Dr Loveman found a range of chocolate recipes in the Earl of Sandwich's journal, written after he became enamoured of the drink while ambassador extraordinary to Spain in the 1660s.

The manuscript includes King Charles II's prized recipe for spiced and perfumed chocolate – which Sandwich reported cost the King £200.

From the 1640s, chocolate was sold as an exotic drink that could cure illnesses and act as an aphrodisiac. The truth often played second fiddle to promotion: one purveyor, Captain James Wadsworth, claimed as early as 1652 that chocolate was "thirsted after by people of all Degrees (especially those of the Female sex) either for the Pleasure therein Naturally Residing, to Cure, and divert Diseases; Or else to supply some Defects of Nature".

As chocolate sellers sprung up across London in the 1650s, a milky version of the drink began to be sold in coffee-houses.

Dr Loveman said: "The novice chocolate drinker of the 1650s and 1660s ran greater risks than money ill spent: he had to bear in mind that the new product might damage his health and there was the real possibility of loss of face through having his inexperience exposed."

The diarist Samuel Pepys tentatively tried chocolate to cure his hangover after Charles II's coronation – apparently with some success. Meanwhile, the poet John Dryden was ridiculed after being repeatedly tricked into paying for expensive chocolate, not realising he was drinking cheaper coffee.

By the 1690s elite 'chocolate houses' were selling the drink to an aristocratic and leisured clientele. Chocolate was widely mentioned in literature, and had already acquired some of the associations with indulgence and pleasure that it has today.

Dr Loveman's research provides an illustration of the social and commercial mechanisms by which an exotic import won English consumers and began the journey to becoming an established part of our culture.

It also reveals some of the continuities in chocolate advertising across the centuries, as well as sharp differences. Dr Loveman added: "Today's chocolate promoters, like some in the seventeenth century, often find cause to highlight women, pleasure, and sexuality.

"In the seventeenth century, however, the fact that frequent chocolate consumption might make you 'Fat and Corpulent' was an attraction, something advertisers now prefer to keep quiet about."

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More information: Loveman, K. The Introduction of Chocolate into England: Retailers, Researchers, and Consumers, 1640–1730, Journal of Social History (2013). Loveman, K. The Introduction of Chocolate into England: Retailers, Researchers, and Consumers, 1640–1730,(2013). DOI: 10.1093/jsh/sht050