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Using an LC-MS instrument, senior Anna Meckel studied how caf­feine, acidity, and antiox­i­dants of several types of tea varied based on brewing con­di­tions. Anna Meckel | Courtesy

It’s a morning ritual for many: boil some water, grab a favorite mug, and puzzle over the tea box — is this a morning for black tea or green? Or what about chamomile? Tazo or Twinings?

The search for the perfect cup of tea was the fuel for — and the focus of — senior Anna Meckel’s bio­chem­istry research. She studied three types of tea for their caf­feine content, their antiox­idant power, and their acidity.

Meckel said she was inspired by a coffee research project done by Sigrid Kiledal ’17, who tested for slightly dif­ferent com­pounds to determine the “healthiest cup” of coffee.

“My interest in tea started in college — necessity drove me,” Meckel said. “Since I’ve become an avid tea drinker…I was inter­ested to see if I could perform a similar analysis of tea: Focus on several tea com­po­nents known to have effects on our health and inves­tigate how factors like tea type and brew method affect those com­po­nents.”

In a world where the steeping processes are more often deter­mined by culture than careful research, Meckel’s findings were sur­prising: of the three types of tea she studied, the brew with biggest caf­feine and antiox­idant punch is Gun­powder Green. And to stim­ulate the brain while still pre­serving tooth enamel, it’s best to steep tea longer, as it max­i­mizes caf­feine content and min­i­mizes acidity.

“I like to oversee projects that stu­dents have per­sonal interest in,” said Lee Baron, pro­fessor of chem­istry and Meckel’s thesis adviser. “This is why we have such inter­esting projects, because stu­dents will say, ‘I saw you did a project on this, and I’d like to do some­thing dif­ferent with it.’”

While coffee’s com­po­sition and brewing methods have been exten­sively doc­u­mented, the recipe for a perfect cup of tea has long been a matter of tra­dition rather than of sci­en­tific tests. Its health ben­efits are often no more than esti­mates based on widely varied brewing con­di­tions.

“It’s well-known that there are dif­ferent ways to do tea,” Baron said. “There’s a way to brew tea in England and a way to brew tea in China. That’s just how you do it. But what Anna is asking is, ‘Is this optimal?’”

The whole world of teas was open to Meckel, so she chose three blends that spanned the spectrum: Gun­powder Green tea, English Breakfast black tea, and Rasp­berry Zinger, an herbal tea.

Meckel said she looked at three com­po­nents in the tea: caf­feine, the amino acid L-theanine, which is known to have a relaxant effect, and the antiox­idant epi­gal­lo­cat­echin gallate, which is one of the most prevalent antiox­i­dants in tea.

In order to isolate and measure these com­po­nents, Meckel used an instrument called the LC-MS: liquid chro­matog­raphy-mass spec­trometry. The instrument does two processes, according to Pro­fessor of Chem­istry Mark Nussbaum, Meckel’s co-adviser on the project.

“A helpful analogy is to think of liquid chro­matog­raphy like a small creek,” Nussbaum said. “If you want to sep­arate some twigs and pebbles, you can do that by tossing them in a stream. The twigs will interact more with the water, and the pebbles will spend more time at the bottom.”

The com­pounds sep­arate them­selves out because some spend more time in the liquid phase, like twigs in the water, and others get slowed down as they interact with the mud and pebbles at the bottom of the creek, like the instrument’s sta­tionary phase, Nussbaum said. Then, with mass spec­trometry, these com­pounds can be iden­tified and quan­tified.

It’s a touchy instrument, Meckel said, and one to which under­grad­uates in many small col­leges don’t have access. Con­trolling the exper­iment at viable brewing tem­per­a­tures while searching for low levels of the many com­pounds in tea caused an extra chal­lenge, Nussbaum said.

But the results were unde­niable, Baron said, and sur­prising: Gun­powder Green tea has more caf­feine than English Breakfast, and the Rasp­berry Zinger fruit tea is much more acidic — a red flag for pos­sible damage to tooth enamel — and lower in antiox­i­dants than the other two teas.

Meckel’s findings on brewing opti­mization are more intu­itive: To max­imize caf­feine and to lower acidity levels, it’s best to steep the tea longer, as more of the caf­feine from the leaves reaches the water and acidic com­pounds dis­solve.

Meckel’s project is just a start in tea research, she said.

“There are so many vari­eties of tea out there that my project shouldn’t be taken as a perfect rep­re­sen­tation of black and green teas as a whole,” Meckel said. “I’d love for someone to inves­tigate more herbal teas like mint, chamomile, or lemon, and a greater variety of steeping times and tem­per­a­tures — maybe looking at iced tea or an overnight extra-strong brew.”