Michelle Francl never expected her book to create such a stir. The 65-year-old professor of chemistry at Bryn Mawr College in Pennsylvania had written a scientific exploration of tea titled Steeped: The Chemistry of Teens.
It was around 200 pages long and was published by the Royal Society of Chemistry at the end of January.
‘I got up in the morning. I got a nice message from my editor saying congratulations on the book launch. When I arrived at my office, there was a note from my publisher’s press team saying, “Would you like to respond to the US Embassy statement?” I thought, “What statement from the US Embassy?”
Some context. In Francl’s book, in a small section on page 168, she suggests that to save overbrewed tea, drinkers should add a pinch of salt. The Internet somehow caught on to this, and by the morning of publication, Francl’s advice had gone somewhat viral.
The US Embassy issued a jokey press release on Twitter saying: ‘Today’s media reports about an American professor’s recipe for the “perfect” cup of tea have landed our special ties with the UK in hot water… We want to ensure (sic) they good people in Britain, that the unthinkable idea of adding salt to Britain’s national drink is not official American policy. And it never will be’. The post got 74,000 likes.
SLAM DUNK: have you made tea all wrong?
‘It was funny and a bit overwhelming,’ says Francl, smiling, sitting in his office with a large mug of (unsalted) tea.
‘I really didn’t recommend (adding salt) as part of general tea making. It’s more of a rescue. And boy, I saw people on TikTok put a teaspoon of salt in. Of course it’s going to taste awful!’ Still, all press is good press, and after Francl and I hang up on Zoom, I purposely overbrewe a tea, then add a careful pinch of salt. Honestly, I can’t really taste it. (And the tea actually looks nice.)
Francl’s book was the product of three years of research. She read more than 500 scientific papers on tea; she connected her mugs to thermometers to calculate the rate at which certain brews lost heat; she used a method involving silicone spheres—typically used to determine the volume of meteorites—to determine the capacity of tea infusers.
She drank a lot of tea. According to Francl, the perfect cup is made as follows.
1 While the kettle is boiling, preheat your mug or teapot by filling it with hot water from the tap. Tea added to an already hot container will stay hotter for longer, and the heat will increase the caffeine and antioxidants released.
2 Ideal mug? Somewhat short and stout (‘almost spherical’) as this has less surface area so it retains heat for longer. Francl uses porcelain mugs ‘with a nice thin rim’, although double-walled glasses also work.
3 Empty the hot water from your pot or mug and pour the boiling water into either loose leaves or a tea bag. (Francl prefers loose, but if using a bag, choose the largest size to give the leaves more movement. The shape of the bag doesn’t matter.)
4 Francl cautions against brewing too long: most tea loses all of its caffeine and antioxidants within a minute of steeping. (For decaffeinated, she suggests steeping a regular tea bag for 30 seconds in boiling water, pouring out the water, and reusing the tea bag in fresh boiling water.) Stirring is also key, especially if you’re using tea bags. Pound and press them as they brew, as this reduces the sour-tasting tannins.
5 Next, milk. Francl takes hers without, but science suggests it’s best to add milk at the end. It reduces the risk of formation. For the same reason, she says that the milk should be warmed up a little. Just enough that it’s not chilled, but not so much that it’s frothy.
While talking to Francl, I also drink a cup of tea – my fifth or sixth day – with a biscuit. How does she feel about pounding, I wonder? ‘Oh no,’ she says firmly. “I don’t like crumbs.”
Other Francl-approved tea tricks include eating grapefruit with your cup of tea (this increases the amount of time caffeine stays in the system) and adding a little squeeze of lemon juice to remove any “foam” on the surface. Francl drinks about four cups of tea a day. In fact, the day the US Embassy tweeted about her book was the first time in about 50 years that she has gone tea-free. “I was too busy!”
She brews them herself – ‘I don’t trust my spouse of 31 years to make me a cup’ – but dreams of ‘someone appearing every morning by my bed with the perfect cup of tea on a tray. But I haven’t been able to train the cat for it’.
Steeped: The Chemistry of Teens by Michelle Francl is published by The Royal Society of Chemistry, £20. To order a copy for £17 until April 7, go to mailshop.co.uk/books or call 020 3176 2937. Free UK delivery on orders over £25.