Researchers at Ohio State University have identified specific molecular compounds that may contribute to the body and mouthfeel of coffee.
While coffee body in academic and industrial settings is often considered in terms of viscosity, the new research suggests small chemical molecules and our mouths’ receptors may have more to do with the perception of the body than the mere physical viscosity of the brew.
In a presentation at the fall meeting of the American Chemical Society (ACS) today, the researchers said the findings could help inform coffee roasters and producers of specialty coffee as they seek specific outcomes for coffee body or mouthfeel.
“We’ve known that coffee itself can impact textural sensations, and it was traditionally thought to be because of sugars and lipids,” OSU sensory scientist Christopher Simons, one of the project’s co-principal investigators, said in advance of the presentation. “But our team finds that this feeling may actually be driven by small molecules, which is kind of unique.”
For the research, the group at OSU enlisted multiple panels of professional coffee tasters, including certified Q graders, to evaluate the attributes of four different coffees. A panel of eight tasters agreed upon a set of references for the sensations found in each cup.
Four tactile sub-attributes — chalkiness, mouth-coating, astringency and thickness — were used to differentiate coffees, while sub-attributes were further drilled down in each coffee sample through liquid chromatography. The results, the researchers said, show precisely which compounds are responsible for specific body attributes.
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For example, the research found that melanoidin compounds formed by the Maillard reaction (first crack) in coffee roasting can be associated with astringency. Meanwhile, the compounds 3- and 4-caffeoylquinic acid were found to correspond with mouthfeel.
The researchers said the work has led to an increased interest in how receptors in the mouth may detect or react to the small molecules that affect mouthfeel, as well as in how coffee production, post-harvest processing and roasting might affect these body-changing molecules.
“Body” is one of the primary categories in the Specialty Coffee Association cupping form, which is widely accepted and adapted throughout the industry for professional coffee evaluation and quality control.
“From our background reading, we found definitions of coffee body to be very vague, and at times, contradictory,” said Brianne Linne, a graduate researcher at OSU who helped lead the investigation, so we thought that this would be an intriguing topic for us to study.”
Support and funding from the research came from the OSU Flavor Research and Education Center.