Michelle Fracl

Tea Tips from a Chemist

Professor Michelle Francl shares her expert advice, based on her new book.

Steeped: The Chemistry of Tea made headlines across the globe and even led to a faux transatlantic tea controversy when Brits revolted against Francl’s recommendation to add a pinch of salt to smooth bitterness.

Reporting on the book and the furor appeared in virtually every major U.K. media outlet, The New York Times, NPR, and local, national, and international broadcasts. 

Now that things have cooled off a bit, Francl shares her tips for the perfect cuppa.

tea bags


Warm your cup, or the teapot, before you make your tea. Keeping your tea at or near the optimum temperature for brewing of 195° F (90° C) will optimize the amount of caffeine you get and give you a more fragrant cup. Swirl a bit of hot water from the tap in your mug or use a bit of the water that you've heated. In desperation I have warmed a cold mug between my hands. Every little bit helps.


Let as little as possible get between you and the tea leaves. For the best, most fragrant cup of tea, use loose leaves rather than a teabag. I get it; teabags are convenient, so choose ones with a lot of space to let the tea leaves expand. If the tea leaves can’t expand to their full size (about four to five times the size of the dry leaves) and still have room left for the water to circulate around them, you won’t be able to extract all the fragrant compounds. If you use a tea basket (a good compromise between a commercial teabag and loose leaves in the pot), use the largest basket you can. Those little novelty infusers are cute but are generally too small.


Keep the water at a boil. If brewing black tea, be sure to use water at the boiling point, 212°F (100°C). Green tea and white tea should be brewed at a slightly cooler 175°F (80° C). Less caffeine and other desirable compounds are extracted when the temperature drops too low. The result is an insipid cup of tea.

Loose tea


Agitation leads to calm when it comes to a cup of tea. Dunking a teabag repeatedly up and down, swishing the basket in your tea, or swirling leaves around in the pot will expose more tea leaves to the water. This increases the extraction of compounds such as linalool, which has been shown to reduce anxiety.


If your tea is overly bitter, take it with a grain of salt. Literally adding a small pinch of salt, not enough to taste, can offset the bitterness of a cup of tea. The sodium ions in the salt interfere with our perception of bitter tastes.


If you need a quick caffeine hit, just 30 seconds in boiling water using a commercial teabag will give you a good dose of caffeine. The cup will not be as complex or fragrant as it could be, but you’ll get that full caffeine zing.


If your afternoon cup of tea is disturbing your sleep, try adding broccoli and other Brassica vegetables to your diet. Regular consumers of these vegetables boost their ability to clear caffeine by about 20%. Need to keep your caffeine levels up? Grapefruit interferes with the body’s ability to eliminate caffeine (and many other drugs).