Elaine Jutamuria ’24 sips coffee with a few drops of anise extract, her second attempt at this.
“What do you think?” asked Omar Orozco, standing at a lab bench in MIT’s Breaker Space, surrounded by filters, coffee pots, and other coffee-making paraphernalia.
“I think it was still pretty bitter when I first tried it,” Jutamria said, musing, “but now that I’ve let it steep for a bit, I think some of the bitterness has gone away.”
Jutamria and Orozco, both current seniors at MIT, are taking Class 3,000 (Coffee Matters: Using Breaker Space to Make the Perfect Cup), a new MIT course starting in spring 2024. The class combines lectures on the chemistry and science of coffee with group projects and hands-on experiments. Their project explores how additives like anise, salt, and chili oil affect coffee extraction (the process of dissolving flavor compounds from ground coffee into water) to improve flavor and correct common brewing mistakes.
In addition to tasting, they used an infrared spectrometer to identify compounds in the coffee samples that contribute to flavor: Does star anise tame the bitterness of the coffee? Does chili oil balance the flavor?
“Generally, if we can recommend it, we ask for it,” Orozco said.
The three-credit “exploration class,” designed to help freshmen explore their major, has been extremely popular, with more than 50,000 students participating. The success of the class is due to its core drink and hands-on approach, which encourages students to ask and answer questions they otherwise would not have considered.
For aerospace engineering majors Gabi McDonald and Mackenzie Dinesen, coffee is appealing, but their classes encourage them to experiment and think in new ways. “It’s easy to bring in people like us who love coffee and say, ‘Well, you have a class where you can make coffee in half the time and try all sorts of different things?'” McDonald said.
Knowledge is spreading
The class combines weekly lectures on topics such as the chemistry of coffee, the structure and composition of the coffee bean, the effects of roasting, and the extraction process with tasting sessions where students sample coffee made with a variety of beans, roasts, and grinds. In MIT Breakerspace, a new space on campus conceived and managed by the MIT Department of Materials Science and Engineering (DMSE), students use instruments such as digital optical microscopes to examine ground coffee beans, and scanning electron microscopes to bombard samples with an electron beam and view cross-sections of coffee beans in incredible detail.
Students form groups and design their own projects while learning how to use equipment to complete guided tasks.
“These projects are sparked by a question they had about coffee during a lecture or tasting, or something they’ve always wanted to know,” says DMSE professor Jeffrey Grossman, who designed and teaches the class. “They then use one or more of these devices to illuminate their problem.”
Grossman traces the class’ origins back to the original conception of Breakerspace, a materials analysis lab and lounge for MIT undergraduates. Opening in November 2023, the space will give students hands-on experience in materials science and engineering, an interdisciplinary field that combines chemistry, physics and engineering to investigate the composition and structure of materials.
“The world is made of matter, and these are the tools we use to understand and make matter real,” Grossman said, so he envisioned a classroom that would “spark discovery and inspiration” for his students.
“The question isn’t pedagogy, it’s, ‘What is the appeal?’ In materials science, there are many different directions to go, but if there is a direction that inspires people because they know it and maybe they already like it, that’s very exciting.”
Cup of Ambition
The attraction, of course, is coffee, the second most consumed beverage after water: it sparks students’ imaginations and inspires them to push the boundaries.
Orozco brought a fair bit of coffee knowledge to the class. In 2023, he taught in Mexico through the MISTI Global Teaching Labs program, where he visited several coffee farms and gained a deeper knowledge of coffee beverages. For example, he learned that contrary to common American belief, black coffee is not inherently bitter. The bitterness comes from several compounds that develop during roasting.
“If you use the right beans and brew it right, you can actually make good coffee,” says Orozco, a humanities and engineering major. A year later, in 3000, he gained a better understanding of how to make good coffee, most notably through a group project he worked on with Jutamria and other students to improve bad coffee.
The team prepared control samples of “perfectly brewed” coffee based on flavor, coffee-to-water ratio, and other criteria covered in class, as well as under- and over-extracted coffees. Coffee that is under-extracted, brewed with not enough hot water, or brewed for too short a time will taste harsh or sour. Coffee that is over-extracted — that is, made with too much coffee or for too long — will taste bitter.
Because these coffee samples contained additives, they were analyzed using Fourier transform infrared spectroscopy (FTIR), which measures how coffee absorbs infrared light to identify compounds associated with flavor. Jutamria looked at FTIR readings taken from samples containing lemon juice to see how citric acid affects the chemical structure of lemon juice.
“Can we find any correlation between what we’re seeing and existing citrate measurements?” asked Jutamria, who studied computing and cognition at MIT and graduated last May.
Another group looked at coffee storage and wondered why conventional wisdom advises not to freeze coffee.
“I just wondered why that would happen,” said Noah Wylie, an electrical engineering and computer science major and coffee lover who owns his own espresso machine.
The team compared methods such as freshly brewed coffee, frozen coffee powder, and frozen coffee beans that were then ground and frozen, and assessed the effects on flavor and chemical composition.
“Then we’ll see which ones taste better,” Wiley said.The team used a coffee evaluation board to record attributes such as acidity, bitterness, sweetness and overall flavor, and combined the results with FTIR analysis to determine how storage affected flavor.
Wiley acknowledges that “good” is subjective. “Sometimes there’s a consensus among groups,” he said. “I think people prefer strong coffee, not weak coffee.”
Other student projects have compared the caffeine content of different types of coffee, analyzed the effect of heating coffee in a microwave on its chemical composition and flavor, and investigated the differences between real and fake coffee beans.
“We gave them some articles in case they were interested,” said Justin LaVallee, manager of Breaker Space and co-instructor of the class, “but for the most part we tell them to focus on what they want to learn more about.”
Drip, drip, drip
Not only will it answer specific coffee-related questions, but it will also deepen both students and teachers’ understanding of the drink.
“Coffee is a complex material. There are thousands of molecules in the coffee bean that change when it’s roasted and extracted,” Grossman says. “The number of ways that this collection of molecules can be manipulated is incredibly diverse, ranging from where and how the coffee is grown, to how the cherries are processed to get the coffee beans, to how the beans are roasted and ground, to the extraction method used.”
Dinesen has experienced this firsthand, for example, discovering that dark roasted coffee has less caffeine than light roasted coffee, dispelling a common misconception: “Just changing the roast of the bean or the grind size can make a big difference in the coffee,” she says. “It’s very tunable, if that’s the word.”
In addition to learning about the science and chemistry of coffee, Dinesen and McDonald also learned new brewing techniques, like how to use a drip funnel. They even incorporated coffee-making and experiments into their study routines, brewing coffee while solving math problems for another class.
“I put my drip coffee maker in my backpack along with a Ziploc bag full of grounds and went to the student center to get the coffee maker, filters and grounds,” McDonald said. “Then I made drip coffee while I was doing the P-set. I also experimented with different amounts of water. It was fun.”
Tony Chen, a material science and engineering expert, reflected on the 3,000 title “Using Breaker Space to Create the Perfect Cup” and whether it’s even possible to create the perfect cup. “I don’t think the perfect cup exists because everyone has their own preferences. I don’t think we have one yet,” he said.
This fascination with the complexities of coffee and the process of discovery is what Grossman hopes to inspire in his students. “The most rewarding thing for me is seeing them develop their own curiosity,” he said.
He recalls the moment early in the class, after his students had learned how to use a light microscope, when they saw, under magnification, the surface texture of a coffee bean, its many different colors and the honeycomb-like pattern of tiny irregular cells.
“They said, ‘Wait a second. What happens when you add hot water to coffee grounds under a microscope? Can you see the brewing process?’ So they took hot water and ground coffee, and lo and behold, it looked different. “They get to see the brewing process right there,” Grossman said. “They have an idea that’s inspired by what they’ve learned, and they experiment with it. We saw that happen multiple times throughout the semester.”
