Q&A with the Author of Steeped: The Chemistry of Tea

If you've been reading any tea news in the last two weeks (and we hope you have!), you have probably come across Michelle Francl's name. Francl caused what could only be equated to a "brew-haha" in recent days when she suggested adding salt to tea as a best practice. Everyone from the U.S. Embassy in London to top news outlets have weighed in on the controversy.

The advice comes from Francl's latest book, Steeped: The Chemistry of Tea, which was published on January 24 by the Royal Society of Chemistry.

Francl, a professor of chemistry at Bryn Mawr College, an Adjunct Scholar of the Vatican Observatory, and a lifelong tea drinker, wrote the book to learn more about the chemical compounds in tea, including caffeine. Steeped explores the chemistry behind different styles of tea and gives advice on how to brew a better cup.

World Tea News caught up with the author to learn more about the science behind tea and her inspiration for writing the book.


What led you to write Steeped?

Michelle Francl: A couple of things collided to catalyze the writing of Steeped. The first is that I've been a lifelong drinker of tea, and as a chemist, am always curious about the chemistry of my everyday life.

The second was a tweet from another chemist wondering about whether or not the shape of a teabag mattered to the final infusion. It made me wonder what chemists knew about the brewing of tea and led me to plunge into the chemical literature to find out. I had read an 1885 paper by a [female] chemist [named] Wilhelmina Green some years back where she carefully investigated the infusion of a black tea. By the middle of the 20th century, there is a rich chemical literature on tea and that continues to the present day.

I also wrote a short essay for a chemistry journal (Nature Chemistry), [and] an editor for the Royal Society of Chemistry Books read the essay and invited me to turn it into a book. Almost three years later, Steeped is the result.


What are some of the more surprising things you learned while writing the book?

steeped the chemistry of tea michelle francl

I learned about the role that caffeine plays in the plant, and about the formation of tea scum and creaming. I had observed these processes but did not appreciate the chemistry behind them and what that might mean about strategies to avoid them. I was also struck by the amount of aluminum and fluoride that can be found in teas in their inorganic form. Finally, I was astounded by the amount of insect DNA that could be extracted from tea. It is one thing to know that it's a natural product, and another to have that kind of evidence.


In the book, do you examine brewing with loose leaves and teabags? Is the chemistry quite different?

Yes, the book treats both brewing with loose leaves and with teabags. The chemistry is a bit different; the resulting infusion contains varying amounts of polyphenols depending on the method. I come down suggesting that nothing should get between the tea leaves and the water and make suggestions about what this means about the size of an infuser, if you choose to use one. Teabags slow down the contact with the water and so change the speed at which different compounds extract. The material some teabags are made out of also absorbs some of the compounds. I routinely use loose leaves, but I know that many people make their tea around the world using teabags.


Has technology had much effect on how tea leaves are produced and infused? 

In many ways, we are still infusing tea in the same way that the eighth century T'ang Dynasty tea masters did. There are methods using ultrasonics to extract tea, but these really are not methods that at the moment are available to those of us drinking tea at home and in our offices. The coffee machines that use pods which also allow you to make "tea" are perhaps the most significant technological innovation, but one I'm going to admit I'm not particularly fond of.


What’s your favorite tea and why?

I have a favorite morning tea and two favorite afternoon teas. I very much enjoy an Assam tea in the morning, one of my favorites comes from the Halmari estate. I appreciate its brisk astringency and significant amount of caffeine, and drink it black with a bit of sugar. In the afternoon, I enjoy a Rose Congou for its floral scent, or green snail tea [Biluochun]. The latter has a lovely grassy aroma and a slightly sweet taste. No sugar for either of those!


Plan to Attend or Participate in World Tea Expo, March 18-20, 2024

To learn about other key developments, trends, issues, hot topics and products within the global tea community, plan to attend World Tea Expo, March 18-20, 2024 in Las Vegas, co-located with Bar & Restaurant Expo. Visit WorldTeaExpo.com.

To book your sponsorship or exhibit space at the World Tea Conference + Expo, or to inquire about advertising and sponsorship opportunities at World Tea News, contact:

Ellainy Karaboitis-Christopoulos, Business Development Manager, Questex

Phone: +1-212-895-8493; Email: [email protected]

Also, be sure to stay connected with World Tea Expo on social media for details and insights about the event. Follow us on XFacebookInstagram and LinkedIn.