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Comment and Chemistry

The chemist who told us to put salt in our tea explains why she did it

After causing an international incident by suggesting that adding salt to your cup of tea will improve it, chemist Michelle Francl says it’s great to see everyone talking about chemistry

By Michelle Francl

26 January 2024

New Scientist. Science news and long reads from expert journalists, covering developments in science, technology, health and the environment on the website and the magazine.

But where’s the salt?

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Chemistry is a field like few others, placing a huge emphasis on the importance of reactions in the pursuit of a scientifically sound outcome. However, even after working in this discipline for nearly four decades, nothing could have prepared me for the reaction this week.

Before publication, I thought that my new book, Steeped: The Chemistry of Tea, might attract some public attention – after all, billions of people around the world love a cuppa, including those from the US, like me. But I hadn’t anticipated brewing up a firestorm that would rage across the Atlantic Ocean – all because of a few grains of salt.

While it might seem outlandish, the idea of adding a pinch of salt to tea in order to reduce the bitterness is rooted in science. Sodium ion is a key element of salt, and it interacts with the chemical mechanism that produces the perception of a bitter taste.

The British people’s love of tea warms my heart like the contents of my favourite mug. That’s a truly special relationship and one steeped in so much history. Needless to say, I didn’t intend to start possibly the biggest beverage bust-up since my compatriots went overboard in Boston 250 years ago – though I have truly enjoyed some of the responses to this global storm in a teacup.

After all, it’s not often that a scientist inspires a viral tweet from the US Embassy in London and I definitely liked the tongue-in-cheek trolling, especially the closer about the microwave. For the British ambassador to the United States to get involved too and for all the world’s media to seize upon a few notes from a 240-page book has blown me away.

Aside from that, it has been very satisfying to see the responses from chemists and the public at large who have so far tried out my tips and enjoyed them. I’ve been a tea drinker all my life, so Steeped has been a passion project for me, a genuine labour of love.

I have spent three years reading more than 500 papers on tea and conducting my own research, testing hundreds of years’ worth of suggestions for making a better brew. My work has tried to uncover the answers to age-old questions, including whether tea is truly addictive; how sugar and spices affect the quality of a cuppa; and how much difference a teapot actually makes. There is so much that has surprised me along the way and I have learned so much during the entire process.

An amusing reflection for me is that, in the end, for certain people, it seems tradition will always trump science. I know that some, like the presenters on Good Morning Britain, might never accept a few of the tips – in their eyes, I am guilty of the most heinous of tea crimes: being from the US.

Joking aside, I hope the sceptics give the science a chance – they just might get a pleasant surprise, as I know what a difference the tips from my research have made for me. No matter where you live, science is science – as the UK Royal Society of Chemistry, which commissioned this book, can attest.

My intention at the start was to write something that not only looks at the fascinating chemistry in a cup of tea, but also presents the research in a way that could perhaps help people think about the world the way scientists do. I believe that’s important because there is so much good that chemistry can – and does – do around the world.

It might seem like a cliché, but science makes the world a better place and can be a real catalyst for change. I want more young people to channel their talents into STEM, facing up to significantly bigger challenges than how to produce a perfect cuppa.

We all know that the importance of chemistry can easily be overlooked by people who might not feel the same passion for our subject. It is my deep hope that this book can inspire the curious to learn more and come inside. When they do, I will be waiting to greet them – with a cup of tea, some warm milk and a pinch of salt.

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