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.”