Chocolate Tastes Better When Warmer, Says WPI Student Research Project

A Key to Chocolate's Taste Is the Nooks and Crannies

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Gabe Cantor

WORCESTER, Mass. - March 29, 2004 - Chocolate lovers can take a cue from mother hens -- when biting into chocolate Easter eggs next month, warmer is better. That was the conclusion of a Worcester Polytechnic Institute student research project, which used the science of surface metrology to analyze chocolate's properties. Gabriel J. Cantor conducted this research as a WPI mechanical engineering student for his senior capstone project, "Scale-sensitive Fractal Analysis of Chocolate."

Cantor broke hundreds of pieces of chocolate at various temperatures, and charted the resulting surface area and texture of the pieces using a scanning laser microscope (the microscope was originally made at WPI as part of a project on runway-pavement texture sponsored by NASA's Langley Research Center). What he found was that the texture of the chocolate pieces became rougher as the temperature was increased.

Next, he observed that the amount of chocolate flavor people sense depends in part on the surface area, or texture, being tasted -- more surface area equals more flavor. Warm pieces with a rough texture offer more surface area for taste buds to savor. Colder pieces with a smoother surface are less flavorful. This is similar to why LifeSavers® candies are more flavorful when biting into them than when sucking on their smooth exteriors.

This led Cantor to his conclusion: If warmer chocolate produces rougher pieces when broken, and, rougher pieces are more flavorful, then, warm chocolate tastes better.

Cantor's faculty advisor, WPI mechanical engineering Professor Christopher A. Brown, notes "While it is fairly intuitive that warmer chocolate tastes better, we didn't really know scientifically why this was. Our lab has conducted research into other chocolate properties for years. So when Gabe wanted to do a project that hadn't been done before, I suggested looking at broken surfaces of chocolate and how temperature affects its surface texture."

Cantor graduated from WPI last May with a bachelor's degree in mechanical engineering. Since graduation, he has been working in the WPI Surface Metrology Laboratory (where he conducted his chocolate research), and is putting the results of the project into a paper he hopes to get published in a research journal.

In scientific terms, Cantor's measurement and analysis of the topography of fractured chocolate surfaces is known as surface metrology -- the study of how surface texture (i.e., topography, or roughness) influences behavior and how surface texture is influenced by manufacturing processes, wear, fracture, growth, disease and corrosion. Through his measurements, he created topographical maps of the chocolate samples. He then analyzed the data using a scale-sensitive fractal analysis algorithm (patented by Brown and two WPI students from the 1990s), which has recently been included in the American Society of Mechanical Engineers's U.S. standards. The effect of temperature on the fractured surfaces was examined. A strong correlation between relative area and temperature was discovered at a specific scale of observation.

While Cantor's project did not aim to determine the temperature at which chocolate tastes best, he was able to establish that the optimum temperature is around room temperature. Finding an exact temperature would require lots more chocolate and many volunteers.

In the fall, Cantor is planning to start work on a graduate degree in mechanical engineering. On a personal note, Cantor's favorite chocolate is Hershey's dark chocolate.

Research projects like Cantor's are undertaken by every undergraduate at WPI as a part of the university's project-based curriculum. These senior capstone projects (known on campus as Major Qualifying Projects) require students to use the skills, methods and knowledge of their major discipline to solve a significant professional-level problem or master a cutting-edge research challenge. They are rigorous academic exercises that are overseen by a faculty advisor and count as a full term's academic credit. At the end of every project, students prepare a report and deliver a presentation of their findings.

The Surface Metrology Laboratory at WPI is the only university laboratory in the United States entirely dedicated to advancing surface metrology. Surface metrology is just one of many areas of materials science and manufacturing research in WPI's Mechanical Engineering Department.

About Worcester Polytechnic Institute

Founded in 1865, WPI is a pioneer in technological higher education. WPI was the first university to understand that students learn best when they have the opportunity to apply the knowledge they gain in the classroom to the solution of important problems. Today its students, working in teams at more than 20 project centers around the globe, put their knowledge and skills to work as they complete professional-level work that can have an immediate positive impact on society.

WPI's innovative, globally focused curriculum has been recognized by leaders in industry, government and academia as the model for the technological education of tomorrow. Students emerge from this program as true technological humanists, well rounded, with the confidence, the interpersonal skills and the commitment to innovation they need to make a real difference in their professional and personal lives.

The university awarded its first advanced degree in 1898. Today, its first-rate research laboratories support master's and Ph.D. programs in more than 30 disciplines in engineering, science and the management of technology. Located in the heart of the region's biotechnology and high-technology sectors, WPI has built research programs -- including the largest industry/university alliance in North America -- that have won it worldwide recognition.