A scientist from the country where you can find tea being made with lukewarm water from the tap claims to have found the recipe for a perfect cuppa.
The secret, according to Michelle Francl, a professor of chemistry at Bryn Mawr College, is a pinch of salt – and energetic squeezing of the teabag.
“You get some awful cups of tea in the US. It’s horrific,” Francl said. “I grew up in the midwest, which is deep coffee-drinking country, but tea has always been my preferred drink – and I have invested a lot of time into studying it.
“But even after all these years of drinking tea and researching chemistry, I learned new things about what is in my cup and how to make the very best cup of tea.”
In less controversial advice, Francl suggests using short, stout mugs as they have less surface area, so keep tea hotter. Pre-heating your mug or teapot is crucial, she says: the warmth increases the amount of caffeine and antioxidants released which, she says, creates vital “aromatic compounds”.
Finally, settling the question that has troubled British tea drinkers and snobs for centuries – whether to be a miffy (milk in first) or not – Francl found that milk should be added after pouring the tea to reduce the chance of it curdling. The milk, she added, should be warmed.
Also key to a perfect cuppa is the use of larger teabags that allow the tea leaves to move around, keeping them in contact with the water – although ideally, you should use loose leaves.
Further advice – that should surely be unnecessary for even the most casual of tea aficionados – is that both teabags and loose leaves should be used only once.
“The research shows that the size of the bag really matters, not the shape, but some shapes give you more space,” said Francl. “Tea leaves expand by maybe a factor of four or five and if you don’t give them enough space, there’s not enough good access from the solvent.
Francl analysed research papers and ancient texts dating back more than 1,000 years to devise the best brew, documenting these experiments in her new book, Steeped: The Chemistry of Tea.
Francl’s pro tips for the perfect brew are:
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Adding a pinch of salt – the sodium ion in salt blocks the chemical mechanism that makes tea taste bitter, especially when it has been stewed.
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Steeping teabags quickly but with plenty of dunking and squeezing – to reduce the sour-tasting tannins created by caffeine dissolving slowly in water.
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Decaffeinated tea can be made by steeping a teabag for 30 seconds, removing it and discarding the liquid, then adding fresh water and rebrewing for five minutes.
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A small squeeze of lemon juice can remove the “scum” that sometimes appears on the surface of the drink, which is formed from chemical elements in the tea and water.
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The aroma of tea is almost as important as the taste – so when drinking from a takeaway cup, it’s best to remove the lid.
