• Religious reservations: Coffee was considered unchristian or oriental; consumption was associated with sin.

  • Medical speculation: In the absence of modern research, heart palpitations, sleep disorders and nausea were easily seen as proof of the harmful effects of the ‘devil's drink’.

  • Social control: Coffee consumption across class and gender boundaries was viewed with suspicion by the authorities.

  • Political nationalism: Coffee was portrayed as a foreign luxury with economic damage – patriotic behaviour meant abstinence.

Gustav III's coffee experiment: How a Swedish king wanted to stop coffee consumption – and failed

Introduction: Historical anecdote about an early human experiment

In 18th-century Sweden, King Gustav III firmly believed that coffee was harmful to health. To prove his conviction, he initiated an extraordinary experiment: two twin brothers sentenced to death were to drink either coffee or tea for the rest of their lives – to find out which drink would bring about death more quickly. This article examines the historical credibility of this story, analyses its socio-psychological significance and shows why Sweden is now one of the most coffee-loving nations in the world.

Coffee consumption under suspicion: how a drink became a threat to public morality

Coffee arrived in Sweden around 1674, but did not gain popularity until the 18th century. It soon provoked a government backlash: between 1756 and 1823, coffee was banned five times in Sweden. An edict issued in 1746 referred to ‘abuse and debauchery’ and provided for drastic measures, including the confiscation of coffee cups.

The official reason given was that it was a health hazard. However, economic and cultural factors weighed more heavily. Coffee was considered a ‘foreign luxury’ whose import was detrimental to the state. Religious and moral arguments also came into play: coffee houses were suspected of promoting idleness, gossip and even political uprisings.

Coffee bans and resistance: from confiscation to coffee parties

Despite all the decrees, coffee consumption remained alive. It was drunk secretly, sometimes with ritualistic defiance: on 1 August 1794 – the day of a renewed ban – Swedes held symbolic ‘funerals for their coffee pots’. Such actions demonstrate the emotional and social significance of the drink far beyond its physical effects.

Even Carl von Linné, the Swedish polymath, warned against coffee, but at the same time appreciated it. This ambivalence permeated all levels of society. Coffee was a social link, especially for women in the city, so the ban also threatened their freedom of action.

The alleged experiment of Swedish King Gustav III: coffee versus tea – both against the lives of criminals

The essence of the famous story: Gustav III pardoned two twin brothers sentenced to death on the condition that one drink three pots of coffee a day and the other three pots of tea. Two doctors were to scientifically monitor the experiment. The king's expectation: the coffee drinker would die sooner. But the story took a different turn: the king was assassinated in 1792. The doctors died before either of the test subjects passed away. Ultimately, the tea drinker died at the age of 83. The coffee drinker outlived him, but the date of his death remains unclear. The story lives on – as the first alleged long-term study involving human twins.

Fact or fiction? The truth in the light of historical research

The experiment is not historically verified. There are no official sources from the 18th century to substantiate the procedure. There is much to suggest that this is a later anecdote intended to dramatically illustrate Gustav III's well-known aversion to coffee. Swedish sources explicitly point out that the ‘truth of the story has not been proven.’

The alleged dangers of coffee: why a drink caused fear

In 18th-century Sweden, several factors converged to foster a hostile attitude towards coffee:

The Enlightenment as a double-edged sword: science meets power

Gustav III acted in the spirit of the Enlightenment: the desire to investigate health empirically was fashionable. At the same time, however, the experiment reveals an authoritarian instrumentalisation of science. The twin study – whether real or invented – illustrates how scientific progress and state control were closely intertwined. From today's perspective, the selection of death row inmates as test subjects raises ethical questions.

From prohibition to national ritual: how coffee shaped Sweden

After the ban was lifted in the 1820s, coffee consumption exploded in Sweden. Within a few decades, coffee went from being a forbidden elixir to a central part of everyday culture. The concept of ‘fika’ – the social coffee break – became an institution.

Today, Sweden is one of the leading coffee consumers across the globe. The story of the ‘coffee experiment’ lives on: as an ironic anecdote, as a myth about scientific hubris – and as a symbol that social habits cannot be permanently suppressed by edict or pseudo-scientific means.

Conclusion: one king, two drinks, many lessons

Whether Gustav III's coffee experiment actually took place in exactly this way is secondary. The story illustrates central conflicts of the Enlightenment: science versus power, freedom versus regulation, pleasure versus discipline. Today, coffee consumption in Sweden is not only a cultural norm, but also the result of a long struggle between prohibition and desire.