Reinventing the (Flavor) Wheel: Industry Collaborates to Identify Coffee Flavor Attributes

Coffee Taster’s Flavor Wheel Revised for the First Time in Over 20 Years

One of the most iconic resources in the coffee industry, the Specialty Coffee Association of America’s Coffee Taster’s Flavor Wheel has been updated for the first time in its 21-year history. The foundation of this work, the World Coffee Research Sensory Lexicon, is the product of dozens of professional sensory panelists, scientists, coffee buyers, and roasting companies collaborating via World Coffee Research (WCR) and the Specialty Coffee Association of America (SCAA). This is the largest and most collaborative piece of research on coffee flavor ever completed, inspiring a new set of vocabulary for industry professionals. This groundbreaking new tool will shift the way our industry thinks about and utilizes coffee flavor.

In 2009, SCAA held its first-ever Symposium in Atlanta, Georgia, with a delegation of over 200 of the most influential and passionate coffee professionals in the industry. It was at this event that we, as an industry, planted the seeds for the establishment of a global organization entirely devoted to coffee research: World Coffee Research. We return to Atlanta this spring for what would have been our eighth Symposium, now Re:co Symposium, with a resource that reflects the hard work and collaboration of so many individuals and organizations for the greater good of the industry.

In the years since its inception, WCR has done amazing work towards its vision, “To create a toolbox of coffee varieties, genetic resources and accompanying technologies, and to disseminate them strategically and collaboratively in producing countries to alleviate current and future constraints to the supply chain of fine Arabica coffees.” Most recently, the work that WCR has done with the development of a coffee lexicon will shed new light on how we describe coffee’s flavor attributes and how this allows us to make decisions about how (and where) coffee is grown.

Over the past few years, SCAA and WCR have been working together to address the fact that our industry needs more scientific ways to research and understand coffee flavor. The SCAA cupping protocol is a valuable tool to understand and evaluate overall coffee quality, but it is not well suited for the kind of scientific research we seek to do in coffee. For example, two coffees might both earn 86 points but taste very different from each other. In order to understand what causes and influences particular flavors in coffee, there must be a better tool for quantifying what those flavors actually are, and quantifying them. What we call ‘flavor notes’—and what scientists call “flavor attributes”—in coffee are especially important here.

WCR determined that a sensory descriptive analysis approach was the way to address this need and move the coffee industry forward. At the cutting edge of sensory science, this method uses panels of specially trained, dedicated sensory professionals to taste coffees blindly against a set of referenced, commonly recognized flavors. We know that having a common language is critical for describing and assessing coffee’s attributes—and that’s exactly what a lexicon is. For this effort, WCR worked with sensory scientists at Kansas State University and Texas A&M to develop the lexicon.

In light of this new research, we at SCAA saw a great opportunity to revise the Coffee Taster’s Flavor Wheel. The strength of WCR’s research, and the importance of the idea of common-language in coffee research, made it clear that it was critical to revise the SCAA flavor wheel to be compatible with the lexicon and bring a new tool to the coffee industry. Although there is strong overlap with SCAA’s original flavor wheel, there are important differences too.

To design the new flavor wheel, SCAA embarked on another groundbreaking research study, this time with the prestigious Food Science and Technology Department at University of California, Davis, to understand how coffee tasters associate these flavor attributes with each other. While the WCR Sensory Lexicon identified a list of coffee flavor attributes, it did not organize them as a flavor wheel does, so we engaged UC Davis to provide some support on this critical component of its development.

The research conducted at UC Davis included over 70 professional coffee tasters and sensory panelists who participated in an Agglomerative Hierarchical Cluster (AHC) analysis, a web-based graphical sorting exercise never before used in coffee research, which was performed to group the flavor attributes into different categories. A Multidimensional Scaling (MDS) analysis was also performed to help visualize where the flavor attributes fell in proximity to one another. This powerful statistical analysis enabled us to group flavor attributes into a hierarchy and arrange them in tiers around a wheel.

The outcome was stunning: both coffee professionals and sensory panelists organized the lexicon flavors very similarly to each other, giving us a high level of confidence in the outcome. This is the first time such a study has been used to organize descriptors on a flavor wheel, making the organization of the wheel as research-based as the lexicon flavor attributes themselves.

SCAA recognizes that other resources we offer will require updates with the release of the new flavor wheel, and that work begins now. It would not be possible to release all of these resources in conjunction with the flavor wheel, but over time the new information will be incorporated into SCAA classes, handbooks, and other resources as needed. This will be an ongoing process, as continual additions to the flavor wheel will be made as the lexicon is updated with newly discovered attributes. Additionally, the opportunity to contribute to the discovery of new attributes will be available on an ongoing basis. All lexicons are living documents, and this work does not stop with the release of the revised wheel. In fact, the wheel is designed in such a way to allow for these changes as new information is made available.

The publication of the WCR Sensory Lexicon and the SCAA/WCR Flavor Wheel is the culmination of over three years of scientific research and collaboration within the specialty coffee community. Dozens of research scientists, sensory experts, coffee tasters, and roasters have collaborated on this project, and it is the most compelling result yet of collaborative coffee science in action. We couldn’t be prouder to celebrate this important milestone in coffee research.

Posters of the new Coffee Taster’s Flavor Wheel are available at