Steeped: The Chemistry of Tea

by Michelle Francl

Tea is the world’s most popular beverage. Dive into a cup of tea with a chemist and discover the rich molecular brew that can be extracted from the leaves of the Camellia sinensis plant. Tea contains over a hundred different chemical compounds which contribute to its colour, taste and scent – and its stimulating effects. The best-known is caffeine, but how does caffeine end up in tea and how can you get it out? Beginning with the leaves, Steeped explores the chemistry behind different styles of tea, from green teas to pu-erh. It tackles the age-old question of when, or even whether, to add milk. And it puts the chemistry to use with advice on how to brew a better cup.

Genres: Nonfiction, Science, Tea

240 pages, Hardcover

Published January 24, 2024

Reviews

[Josh Nisley · Rating 4 out of 5]

I still don’t know how to read molecular structures, but this is a fascinating study of what tea is and how it works—and how to brew a better cup.

[Brian · Rating 5 out of 5]

I was first introduced to this book because of the controversy it generated. Apparently the British don't like Americans adding their voice to the conversation on tea (there may be historical reasons for this). That alone was enough to convince me to read it, and it was well worth it.

The chemistry presented was fantastic. Organic chemistry is a challenging subject, but the presentation is clear and easy to understand. The section on the big ideas in chemistry was more helpful than any science course I've ever taken. This book has given me a basic grasp on organic chemistry (which could not be said for high school chemistry), and a better understanding of chemistry in general. As Francl says, chemistry is just specialized cooking, so a book on food is the best way to learn chemistry.

And, of course, if you are a massive (or aspiring) tea nerd, this is the book for you. It's got loads of practical tips for how to brew and enjoy a better cup of tea, which I am definitely going to be using.

[Debbie Mitchell · Rating 5 out of 5]

As a chemist and a tea drinker—I loved this book!!

I thought Francl did a really great job explaining several topics in chemistry in a simple way.

The main concepts of this book are:
(0) atoms are the building blocks of matter
(1) the function of a molecule is determined by its structure—not its original source
(2) opposite charges attract one another.
(3) the dose makes the poison

I really loved that at the end of each chapter Francl reminded the reader of the main conclusions through her section : Brewing a Better Cup—where she shared how you can practically make a better cup of tea based on the principles of the chapter. And some of the guiding principles depended on if you prefer the complex taste of tea from the many different molecules extracted from the tea leaves or if you’re just interested in the caffeine.

This book was so nerdy I loved it. She showed the % of caffeine extracted from tea leaves as a function of time (you don’t need much longer than 4 min if you maximize caffeine without extracting too many other bitter alkaloids)

There is an entire chapter on how caffeine interacts with our body. Why it keeps us alert, prevents us from sleeping, and why it can make your ibuprofen more effective.

I also really appreciate that Francl highlighted many women in chemistry. I learned that the planar structure of benzene was worked out by Dame Kathleen Lonsdale while she cared for her newborn daughter.

I learned that the concept of the null hypothesis originated when a biochemist claimed that she could tell the difference between two cups of tea one with milk added first and one with tea added first.

Overall highly recommend this book! It was a lot of fun and I learned so much!

[Salv Nigrelli · Rating 4 out of 5]

Read on a 7h train journey before visiting China’s National Tea Museum. I really enjoyed this one - it treads that fine line of appealing to both non-scientists and scientists reasonably well. It’s the first edition so there are a few teething problems - a couple of sections are repeated and some of the figures are a bit jarring, but nonetheless a very fun read :)

[Elena · Rating 4 out of 5]

nice and informative, but I was hoping for more detail

[Theresa Timlin · Rating 4 out of 5]

As a tea drinker and as a Bryn Mawr alumna, of course I had to read this book on the chemistry of tea by Bryn Mawr professor Michele Franck. My only chemistry class was the introductory course in college. I found this fascinating and wished I had Dr. Francl as my teacher back in the day. Plus now I understand how to make a better cup of tea.

[Simon · Rating 4 out of 5]

A quick read - interesting and informative. Knew a few things in here and as a chemist I could follow relatively easily, but it also seemed to be written that a non chemist could follow.

[Elizabeth Ruth-Abramian]

In “Steeped: the Chemistry of Tea”, author Michelle Francl discusses the all of the interactions of chemical substances in tea leaves and water when they are infused as a drinkable brew.
Throughout her book, Francl describes the details of chemical reactions that determine the flavor in your tea.
“Steeped…” gives ample references at the end of each chapter, and illustrations in black and white attend each chapter section. Most illustrations are diagrams of molecules, and there are also charts and tables. What some readers would recognize as standard Chemistry literature made me gasp as I leafed through the book. “Oh no!” I thought, “I’ll never grasp the meaning in this book!”
I hadn’t discovered the missing link to the subject of Chemistry. Until I read “Steeped …”.
One thing I’ve gathered from prior experience is that making connections depends on a willingness to look at a subject from different angles. When I saw this title, I was immediately drawn to the idea. So, unwilling to let the chemistry of tea go (!) I leafed through the chapters until I found something I could grasp.
It turns out that the last chapter, the one on the physical (and therefore tangible) aspects of tea-brewing looked quite accessible. Francl’s title for it, “Earth, Wind, Fire, and Water” is a detailed view of the technology of tea-making.
In the chapter, which is a colorful description of tea-technology, Francl examines the sizes and shapes of objects used to brew tea, and brought me a sense of clarity on the meaning of chemistry and tea. I thought a point of entry might help me apply my curiosity to some of the earlier chapters on the hard science I had so often found mystifying.
Reading “Earth, Wind, Fire, and Water”, I found lots of details about teabags. Teabags control the caffeine and antioxidants plus iron that I may get along with the tea flavor I’m craving.
It turns out that teabag sizes and shapes, not to mention the materials they are made of, contribute much to the taste of tea. I was surprised to learn that size, or surface area of the teabag can impede or increase the caffeine content of your tea. On top of that, depending on your habits for dunking your teabag, how close to bedtime is safe to drink it, and many other qualities you didn’t know existed. Moreover, some of the most recent and new teabag materials may also contribute to what’s known as “plastic contamination” both in the environment and in our stomachs!
In “Steeped …” you’ll learn about the components of tea, of course. You’ll also see the relationship of different substances in tea leaves themselves such as polyphenols and how these are affected by brewing times.
Also, the chemistry of flavorings and additives such as milk and spices, the chemistry and behavior of H2O, or water are described. It turns out that water temperature influences taste, but also is responsible for how much caffeine is experienced by the tea drinker. Francl says:
“Tea steeped at 4 degrees C for a full 24-hours has only 1/3 of the caffeine of the same tea steeped for 20 minutes at 90 degrees C.” – p. 132
What I find so fascinating in Francl’s accounts is her dedication to revealing history, the back-story to what we know today about tea. You’ll discover a number of references to recipe books, industrial inventions, and even the philosophy of tea and tea-drinking from the Chinese author Lu Yu, who wrote the Classic of Tea, in the 8th century.
There is so much about tea-drinking history that applies in chemistry. She says that over the past 140 years :
“Chemists have identified more than 2000 different molecules in tea infusions … tea is a natural product where every type of tea … is different … ”-p.81
One of these molecules is L-theanine. It can, along with caffeine, reduce anxiety and induce a super-relaxed feeling. The author recounts that adding a small amount (250mg) to her teacup helps reduce stress.
Besides the good molecules found in tea leaves, there are some that come with warnings attached. One of these is---surprisingly—fluoride, which you might be concerned about if you live in an area where your drinking water is also high in fluoride.
I’ve focused on the technology of tea in order to point out that things we might all know and share about brewing tea can be viewed as an entry point to the science of chemistry!
The second most fascinating thing about this book is the main point. I think the author must have considered that pairing things we are already familiar with with the chemisty behind them would greatly influence our understanding of the science. Taken as a whole, “Steeped …” examines all the things we are familiar with, but haven’t considered if we lack a background in chemistry.
6 more chapters discuss topics such as “Chemistry’s Big Ideas” and the structure of molecules. In case there’s any question, you are getting a first row seat in the lecture hall where the inscrutible is about to come out into the light of day. But gently. All it takes is to relate one familiar thing to an unfamiliar one, and you will, if a tiny bit patient, begin to get a handle on this thing called the chemistry of tea.
The remaining topics include: the methods used to cure tea leaves and ready them for market; what caffeine does once inside the body; descriptions of the constituents of tea leaves such as tannins, acids, alkaloids (bitter substances), and minerals that impact taste; how to brew tea; and one of my favorites to refer back to---the actions of spices, proteins, sugars, and other additives on your cup of tea.
A thoroughly researched treatment of the chemistry of tea, this book is eminently readable whether or not you are a chemist. I believe it will be a resource for me whenever a question pops up about whether ingredients I want to combine in tea will actually go together well!

[Scott Milam · Rating 5 out of 5]

Lots of great stuff to use in my chemistry class

[Julie · Rating 5 out of 5]

I love tea. I sip every day. I have more than 100 different varieties and flavors of loose leaf teas in my tea stash. Anything from herbal to pu'erh to rooibos...I've got it and brew it. I mix my own tea blends. I work from home and tea breaks are my moments of zen during the day. Taking time out for some tea brings me peace, clears my mind, and refocuses me. I've spent years learning about tea and perfecting my brewing skills. I make a great cup of tea.

So, of course I had to read a book about the chemistry behind tea!

I heard about this book due to a controversy stemming from the author recommending a pinch of salt to offset the bitter taste of overbrewed black tea. (She's totally right....just a very tiny amount of salt added can save a bitter cup of tea. I've tried it.) I spent years perfecting my tea brewing skills and my tea blending skills. I've gone from a cup of microwaved water and a cheapo grocery store tea bag to sampling rare varieties of loose leaf teas with all manner of brewing requirements. There really is a learning curve to the perfect cup of tea.

My tea journey and everything I have learned about how to make a proper cup of tea made me want to read this book. The Chemistry of Tea -- yep, I wanted to know the science behind the lovely aroma, taste and differences between my favorite types of teas.

And Michelle Francl delivered just what I wanted!!

This book covers the molecular makeup of tea, what chemicals are present in the leaves, the differences in processing that creates different types of teas, how to brew, when to add milk, sugar, honey, and much more.

I made it into part of my tea ritual for an entire week.Steeped has 7 chapters, so this worked perfectly. Each chapter starts out with a tea pairing recommendation. When I got up each morning, I brewed the tea of the day and read one chapter in this book. So much information! Very interesting and just fun to read.

I am not a chemist. I did remember some of the facts she shared about basic chemistry from my public education, but a lot of the science facts were new to me. I loved the information about what makes tea smell and taste the way it does, and how the processing of the leaves makes a huge difference in the taste profile of the tea. That's how leaves from basically the same plant can become black, green, oolong, white, or pu'erh tea.

And brewing matters. You can't just microwave the crap out of a mug of water and plunk in whatever tea bag, leave it for a bit and have a great cup of tea. And, cheap tea makes cheap tasting tea. I grew up with Lipton tea bags tossed in microwaved water until the result looked dark enough....bit of sweetener thrown in...that was tea. Is it drinkable? Yep, for the most part. Is it good? Nope. And, Francl's book gave me the science to back up the fact that quality of tea and how tea is brewed really matters.

The science she shares totally backed up the tea skills I have learned over the years. I start each day with an excellent cup of tea because I'm doing all the right things. And after reading this book, I know why those brewing skills create a great cup of tea.

Those who aren't into science might find this book a bit off-putting or overwhelming at first. But, it's only 7 chapters. Even if the discussion of chemistry, diagrams of molecules and explanations of what chemicals are present in tea leaves isn't riveting, there is a lot of information on tea itself, brewing, why changing up certain things can change the taste and aroma of the tea in your cup.....

I recommend this book to every tea lover! I learned some new brewing concepts that I've put into practice (like warming my cup up first before I pour any tea into it -- it makes a difference!) and learned to really appreciate all the wonderful science that goes into the aroma and taste of my tea.

The moment of zen I feel when I bring a mug of fresh tea up close to have that first sip of the day....the steam, the lovely aroma....the flavor....is all backed up by science!

Thanks Michelle!

[Emily Marie · Rating 4 out of 5]

This was such a great, nerdy read on the chemical world in your teacup. It was written very attainably, every chemistry concept was explained in the text as needed and in a simple fashion (at least as far as my chemist sensibilities can tell) It was also very witty and didn’t take itself too seriously, which was really nice. I was kind of nervous about this taking on too much of a western, British lens of tea drinking in a bad way (it was published by the royal society of chemistry, a British chemistry organisation). My feeling is that it did a good job honouring the roots of tea and the cultures it comes from (specifically China and India). It didn’t spend much time on this, because it did concentrate largely on the chemistry of what is happening in your tea cup, but it definitely didn’t pretend that British tea culture was the beginning or end-all-be-all of tea.
There was a chapter at the end that talked about how things commonly added to tea interact with the molecules in tea that made it obvious that the audience was expected to be from the US or UK though, because while things relevant in other tea cultures were discussed, the text did treat British tea culture as the „known“ or „familiar“ element. I don’t necessarily think that is a bad thing, (every text has an intended audience), I think it is important to mention.

[Ankit Sharma · Rating 5 out of 5]

Steeped: The Chemistry of Tea" by Michelle Francl is a captivating exploration of the world of tea, blending science with the art of brewing. Francl, a distinguished chemist, delves into the molecular complexities of tea, unraveling its fascinating chemistry in a way that is accessible to all readers.

Through meticulous research and engaging storytelling, Francl reveals the secrets behind tea's flavors, aromas, and health benefits. She explains how different types of tea, from black and green to oolong and white, are processed and how these processes impact the final brew.

What sets "Steeped" apart is Francl's ability to seamlessly weave together scientific explanations with cultural anecdotes and historical insights. She takes readers on a journey through time, exploring tea's origins in ancient World and its global spread, highlighting its significance in various cultures and traditions.

Francl's passion for tea shines through in every chapter, making "Steeped" not just a scientific exploration but also a love letter to one of the world's most beloved beverages. Whether you're a tea connoisseur or simply curious about the science behind your daily cup, this book is a must-read. It will deepen your appreciation for tea and leave you with a newfound understanding of its rich and complex chemistry.

[Popup-ch · Rating 4 out of 5]

A short, semi-scientific introduction to tea making, focusing mostly on the steeping process with some digressions into the growing, processing and post-use recycling. There is a long chapter focusing on caffeine, working as an adenosine blocker. Caffeine is among the first molecules to dissolve when steeping tea, and most of the caffeine has already been dissolved in about 30 seconds if using a tea bag, and a in 90s if using loose leaf.

One interesting titbit is that the ISO standard for making tea (ISO 3103), makes a very bitter brew, as it recommends 20g of tea per litre of water, and steeping it for six minutes. Ms Francl recommends 2g of tea for 200ml of water, which is still significantly stronger than I normally make it. (I tend to go for about 7g of tea for 1.5l of water, or about half of Ms Franlc, and one quarter of the relevant ISO standard.

When the book came out, there was a huge hullabaloo abot the fact that she suggests that a pinch of salt can alleviate some of the bitterness in the tea. This caused huge headlines at the BBC, but in the book it is mentioned only in passing as an interesting insight into the human perception of flavour. Normally you'd want the bitterness, as it's an integral part of the flavour profile of the tea, though.

[Susan Olesen · Rating 4 out of 5]

Heavy on the chemistry - it's been 40 years since AP Chem, so I had to think a bit, the book explores the molecular details in making the perfect cup of tea. While yes, doing so can result in an amazing, mind-blowing cup of tea like the Buddhists promise, I'm not above forgetting my tea in the microwave for 30 minutes, reheating it, and drinking something almost solid in its tannins and accepting the bitterness as the price to pay for forgetting about it.

Not everyone is going to be this deep into their tea, but for those who are, it's a nice, fairly short treatise on the chemistry of tea, from types of leaves to caffeine levels, bags vs. balls, microwave vs. boiled soft water, and every other possible detail imaginable. It will answer questions that honestly I have asked myself, like "what is that white swirl on the tea when I microwave my brew?" How do they decaf the tea? (It's actually very simple).

While you don't have to have a chemistry background, at least basic science would be a help. If you aren't of a somewhat scientific mindset, this book might be one you want to skip. Otherwise, I enjoyed it.

[Mark Eichin · Rating 5 out of 5]

Gloriously detailed - How Tea Works at the chemical level, without assuming too much current chemistry on the part of the reader (one could reasonably use the first couple of chapters as a refresher on the "big ideas" of chemistry in their own right, though it is always in support of Tea itself.) At the same time not *clinical* - the author clearly *enjoys* tea and the associated rituals, while using science to understand the mechanics and dispel myths.

Well footnoted, I ended up adding Inventing Temperature: Measurement and Scientific Progress to my reading list from a mention in a later chapter.

[Mick de Waart · Rating 3 out of 5]

I liked the book but I expected more from it.

Partially, this disappointment is a matter of arbitrary preference: the book is mostly about ‘British’ or western tea culture while I’m more into Chinese tea culture. Some questions I would’ve liked to see the author get it to: what is the chemical process behind yixing teapots influencing teas brewed in it over time? How does gong fu brewing work?

But for another part I would’ve liked it if the author went a little deeper into the chemical composition of tea itself and specifically the differences between different teas. She goes into this for a little bit but I would’ve liked to know more about which compounds give different teas their characteristic aroma’s.

[Claire Binkley · Rating 5 out of 5]

This book explains why I am so fond of some substances and absolutely can't stand certain others. I found it enlightening. It talks about why people like to add a couple things like parmesan cheese and MSG to food (and what exactly that is, too, without sounding like a particularly dry textbook).

I think it does a better job of explaining the difference between green, oolong, and black tea than I remembered.

While I wouldn't go about making my tea too cheesy and I remember being rather scared of MSG from hearing horror stories about it in my Chinese food when I was younger, I still found this book particularly interesting!

[Carissa · Rating 5 out of 5]

I absolutely adore this book as it combines my two favorite subjects (food and science) in the nerdiest way possible. While the author does her best to dumb down the chemistry to make this a more accessible read for all, it IS all rooted in organic chemistry and you will learn the basics or, in my case, relive your semesters of O Chem all over again. And as someone who actually enjoyed those semesters, that makes my heart happy. While it may not be for everyone, this could easily end up being my favorite read this year!

[Nicole · Rating 4 out of 5]

A fun, engaging guide to making a better brew. It answered so many of my questions (to re-steep or not? What does L-theanine really do? What about that whole microwaving controversy?) There is no false advertising here - there really is a LOT of chemistry in this book. But it’s all very well explained and highly accessible. If you love tea and are curious to learn more, this book is for you.

[John Fetzer · Rating 5 out of 5]

The science of tea for the non-scientist

An interesting and wide ranging overview of tea and steeping it to make a good cup of tea. The chemistry and physics are covered and aim to enlighten the lay person.

[Nichola · Rating 4 out of 5]

This book is exactly what it says- a chemist explores tea. If that is what you are interested in, its clear and informative. She answers many questions, but also I am left with the understanding that there isn't one correct way to approach the drink, however you like it best is prefect.

[Matthew Gilmore · Rating 2 out of 5]

Very lumpy mixture of disparate elements--tough read.

[Katrina · Rating 5 out of 5]

It feels like this book was written specifically for me. It answered all my tea questions and has already changed my habits. I will be dipping into this again for sure.

[Marguerite Gratton · Rating 1 out of 5]

OMG - so boring. About 10 pages were interesting. Brutal read

[Carolyn · Rating 5 out of 5]

Excellent book. I really enjoyed it. There is a lot of chemistry and I think having done higher level chemistry helps but it is a book for anyone that likes tea!

[Michael Butterworth · Rating 5 out of 5]

Dr. Francl makes the chemistry of tea interesting and engaging, even for non-specialists. A must-read for anyone who wants to know a little more about the most consumed beverage on earth.

[RuBisCO Reviews · Rating 5 out of 5]

I wish my chem proffs in undergrad would have just used this book as it hits on the things you actually want to know about chemistry from a great perspective.

[Justin Ma · Rating 2 out of 5]

This isn’t a book teaching about tea using chemistry, it’s a book teaching chemistry using tea. Not that that’s a bad thing.