Chemistry professor gave unusual advice on enhancing the invigorating effect of tea

If you feel like the energizing effect of your morning cup of tea has quickly worn off, the scientist behind the controversial advice to add salt to your tea has a more palatable tip: try grapefruit.

Michelle Frankl, a chemistry professor at Bryn Mawr College, caused an international teacup storm last month by suggesting that a pinch of salt could create the perfect drink, The Guardian recalls.

Now she has advice that is much less likely to reignite the biggest transatlantic tea scandal since the American Revolution. Speaking at an online webinar organized by Chemistry World magazine, she said fruits and vegetables can prolong or reduce caffeine intake.

“If you eat a lot of grapefruit, you can increase the time that caffeine stays in the body,” says Michelle Frankl. “And if you add kale, broccoli and Brussels sprouts to your diet, you can get rid of caffeine faster.”

She said the reaction to her book’s advice to add salt to tea “baffled her” – especially the diplomatic interventions that followed – and that the American approach to making the drink was not to her taste.

Her advice sparked outrage and prompted the US Embassy in London to post on Platform X that “the unthinkable idea of ​​adding salt to the UK’s national drink is not official United States policy. And there never will be.” However, the rest of the message ended reassuringly: “The US Embassy will continue to brew tea properly – in a microwave oven.”

Professor Frankl expressed disagreement with the American habit of using a microwave oven to make tea. She said this approach promotes the formation of a cloudy material known as foam, which is composed of organic matter with calcium and magnesium carbonates.

“This happens when you microwave tea because you are bringing it to the boiling point so quickly that you are not removing the oxygen and carbon dioxide. Thus, there are more carbonates in the water, and oxygen also promotes the development of organic substances, which lead to the formation of many floating substances,” explains the expert.

Frankl said the surprise about the previous comment—that the milk should be heated—was something of a misunderstanding, noting that she didn’t mean that it should be heated.

“But in fact, cold milk from the refrigerator poured into hot tea can actually curdle,” she said.

Frankl stressed that the size and material of the tea bags matter, but not their shape, while it is important to preheat the teapot before use to ensure the water doesn’t get cold when added.

“At 60°C, the total amount of caffeine extracted is about half that at 90°C,” she said. “If the water you use to make your tea isn’t hot enough, you won’t get the caffeine hit you’re hoping for.”

For those who like calming drinks, Frankl advises that Earl Gray is best because it contains more of a substance called linalool due to the citrus oil it contains.

“It turns out that linalool activates the same pain-relieving pathways as opioids,” Frankl says. Inhaling the aroma has been shown to reduce pain perception in mice and anxiety in humans.

“Earl Gray tea with such a distinctive aroma is something that can reduce anxiety in people. Therefore, when my husband drinks this cup of tea before a meeting in the department, it means that he is up to something,” the professor notes.

Scientists have discovered that there is one more important ingredient to making the perfect tasting tea: microbes.

In the journal Current Biology, researchers reported that different tea varieties are associated with different soil microbes, and that varieties associated with microbes involved in nitrogen metabolism contain higher levels of the amino acid theanine, a substance that contributes to the drink’s flavor.

“Our results suggest that the taste of tea may be influenced by soil microbes, as we showed that microbes influence theanine levels,” said Zhenbiao Yang, co-author of the study from Fujian Agriculture and Forestry University in China.