How to make the perfect cup of tea (and cut a cake)

tea and cake

Scientists have been studying tea brewing for at least 150 years. We explain how to make the best tea, and how to cut an Easter cake without letting it go dry

Materials scientist Prof Mark Miodownik has been in the news recently because of his claims that there are four basic rules to making a perfect cup of tea (use fresh water, get the temperature and volume right, let it brew and put the milk in second). While this might be a simplification of the 11 rules laid down by George Orwell seventy years ago, Miodownik’s conclusions are in agreement with those of a scientist working over a century-and-a-half ago, Francis Galton, who had just three rules for a perfect cup of tea.

Better known as the ‘father of eugenics’ – he defined the term and wrote several works about how positive and negative characteristics were inherited (and could be bred) in humans – Galton was a polymath who worked on a huge range of scientific topics, from tea and cake to meteorology and fingerprint technology. His tea studies are often mentioned in biographies, but most authors don’t say that his studies focused on tea drinking while travelling, and the findings were published in his book, The Art of Travel, or Shifts and Contrivances Available in Wild Countries.

Three rules for the perfect cup of tea

The Art of Travelfirst came out in 1855 and had multiple editions, with information about tea appearing from 1860; in the final fifth edition, published in 1872, he summarises his tea-research in a section marked “theory of tea-making”, as part of his advice on “bush cookery”.

Do not use boiling water: steep for eight minutes

Galton had a lid made for his teapot with a hole in it for a tube capped with a cork, so that he could insert a thermometer into the pot. He also experimented with how fast the water cooled in a teapot, and found that his perfect cup of tea was usually made with water between 180 and 190F (82-88C), and brewed for eight minutes. Tea steeped longer or in hotter water was bitter; tea in colder water was “flat”. Of course, everyone’s taste varies, but Galton says we can all make a perfect cup of tea every time if we just pay attention to three things:

to time, and quantities, and temperature. There is no other mystery in the teapot.

Throw away the teabag, or make it Australian style.

Galton goes on to discuss making tea without a pot or mug, and actually favours a teabag – or at least a muslin bag to keep the leaves in. The advantage of this, he says, is that it can be thrown away after being used, leaves and all. Or you can do as the Australians do, and make it in a small quart pot, pour sugar in a pint pot, and then pour the drink from one to the other until mixed thoroughly.

But what about the cake?

This is a question for fans of Alex Bellos’s Monday Maths Puzzle: the challenge here was to cut a cake fairly to feed two people, without letting it go dry in the meantime. The solution is a non-intuitive series of cuts (illustrated here) that allow the pieces to be pushed together, preserving the shape of the cake and preventing them from drying out – a “common india-rubber band” holds the cake together firmly while you eat.


This may all seem very cosy, but Galton is a difficult man to have as a public face for science. His travels in Africa were part of a growing movement in scientific exploration that involved mapping and measuring the land (and its people). The data this produced was used for military and colonial purposes, to invade countries, to subdue and control indigenous people; and sometimes to portray these people as backwards, barbaric, less than human, and not able to be part of a modern, western, civilisation. Galton rated the ‘African negro’ as nearly the lowest grade of human being in terms of intelligence and potential (with Australian Aboriginal people as the ‘lowest’). It is no coincidence that Galton’s first book about his African travel, Narrative of an Explorer in Tropical South Africa, was published in 1853 – the birth year of Cecil Rhodes, a man who later justified his self-described “despotic” rule of an African country by arguing that the native people were barbarians, while whites were “the first race in the world”.

The Galton Laboratory for Eugenics was part of UCL from 1907 to 2000, although in 1963 the word “eugenics” was removed in favour of “Human Genetics and Biometry”. Galton is, like Rhodes, still remembered in the names of events and buildings, and in paintings and statues, especially at UCL, which is perhaps ironically where the latest tea research took place. It remains a difficult legacy for scientists to handle.

Powered by article was written by Vanessa Heggie, for on Tuesday 22nd March 2016 12.23 Europe/ © Guardian News and Media Limited 2010