February 10, 2016

The World Coffee Research Sensory Lexicon: It’s New, But Is It Finished?


Only the new SCAA Flavor Wheel could keep one hundred highly caffeinated coffee professionals absolutely silent.

SEE ALSO: Specialty vs Commercial Coffee: 3 Key Processing Differences

The anticipation was palpable. We were at the University of California, Davis, for the first-ever SCAA Sensory Summit: two and a half days of coffee geekiness. And the unveiling of the updated flavor wheel was to be the event’s grand finale.

The SCAA Flavor Wheel & World Coffee Research Sensory Lexicon: A Paragon of Coffee Science

As a coffee producer in Mococa, Brazil, it was the kind of event I live for. UC Davis has one of the premiere food science programs in the world. They hold several patents in the food and beverage industry and are particularly well-known for their taste-driven work in the wine world. The leafy and pedestrian-friendly campus is composed of every imaginable department of science. Essentially, it’s the perfect location for an international event dedicated to furthering a science-based approach to coffee.

The grand finale – the revised SCAA flavour wheel. Credit: @ibrewmyowncoffee

Present with me were coffee producers from Central America, experienced coffee roasters, baristas, and green coffee buyers from North America, Europe, and Australia. SCAA had a discerning lot to impress – and they succeeded.

The course (SCAA Sensory Summit), compiled of nine sessions, two SCAA courses and a series of expert-led presentations, met all of our expectations. We geeked out; discovered new chemistry equations for coffee extractions; learned about honey, olive oil, and wine; and talked non-stop about coffee.

After eight years in the industry, you start to feel like you never get to see or learn anything new. This course was reinvigorating.

In fact, the class was so spectacularly nerdy that my college friends threatened to stop following me on Instagram – apparently I’d become too boring. (Is coffee science boring?!)

Coffee calculations at SCAA Sensory Summit

Serious Instagram potential right? #coffeegeekery

And the SCAA Flavor Wheel based on research studies conducted by the Food Science and Technology Department at UC Davis, was a visually stunning and impressive piece of sensory science.

In short, UC Davis and the SCAA took a research-based approach to visually organize the 110 coffee flavor, aroma, and texture attributes identified by the World Coffee Research (WCR) Sensory Lexicon (read here). The groundbreaking lexicon is the largest and most collaborative piece of coffee flavor research ever undertaken and takes a sensory descriptive analysis approach to define a common language for describing and assessing coffee’s possible attributes (download the PDF  here).

SCAA Flavor Wheel

The newly designed coffee flavor wheel. Credit: SCAA

In the above wheel, you may notice how the attribute ‘cells’ appear to be a different distance from one another. If two attribute cells are connected, it means that the professional tasters in the WCE research thought of these attributes as being closely related, and if there is a gap, that means the tasters thought of them as being slightly less closely related. The further the gap extends to the center of the wheel, the less closely related the tasters found the attribute descriptors to each other. This might be helpful when ‘calibrating’ coffee descriptors to other tasters’ experiences, or designing taste descriptors that are intelligible to the maximum number of people.

Breaking Down the World Coffee Research Sensory Lexicon

The WCR took on the task of evaluating 105 Arabica coffees from 13 countries. In total, they came up with 110 attributes to describe coffee’s flavor – far more than most other food items receive. For each, they provide a definition of the attribute (so “blackberry” is the “sweet, dark, fruity, floral, slightly sour, somewhat woody aromatic associated with blackberries”) and a set of reference flavors and/or aromas (many of them items that could be found in a grocery store in the US).

Sensory scientists can use these references as benchmarks for the intensity of a given flavor in a coffee sample. The intensities can be rated on a scale of 1 to 15 for each lexicon attribute. For example, when evaluating a coffee sample that has a blackberry note, the scientists would taste the coffee against the reference, Smucker’s Blackberry Jam. They decide whether the intensity of the blackberry flavor is more or less than the intensity of the reference (5.5 for flavor) in order to then assign it the appropriate numerical score.

world coffee research lexicon 2016 wheel flavour

The following is outlined for each attribute; name, definition, reference(s), intensity score, preparation instructions.

The Effect of the Sensory Lexicon on Specialty Coffee

The development of such a precise and scientific tool enables us to create a shared language for, and measure of the intensity of, a coffee sample’s possible flavors – which can only benefit us. After all, specialty coffee is an industry centered around flavor. As World Coffee Research stated here, the lexicon will be used as a research tool – “the lexicon is an essential tool that’s been missing for coffee researchers for too long. Measuring coffee’s flavors and aromas is the necessary first step to understanding what causes coffee to taste, smell, and feel the way it does.”

Recognizing that it had great potential for industry, the SCAA applied the lexicon as the basis for a new flavor wheel.

This wheel is the formation of a language designed purely for the communication of our product. Yet this wheel doesn’t just give us the language with which to describe specialty coffee; it also defines it. The words it uses will dictate how we will describe our coffee from here on in, on a global scale.

As someone who works with coffee in Brazil, I looked at this wheel and thought: but what about the tartness of a pitanga, the sweetness of cupuaçu, the astringent dryness of caju, the bright sourness of bacupari – and how are these any less important than maple syrup or blackberries?

The Sensory Lexicon: A Living Document

I was initially disappointed by the North American-centric nature of this wheel; however, my mood was soon improved – by a letter published on Facebook by World Coffee Research.

World Coffee Research admit that the lexicon is an unfinished project, but they also have plans to improve it, with our help. They want us to assist with filling in the gaps in the attributes by submitting flavors, meaning that the pitanga, the caju, and all the other flavors from around the world still have a chance to appear. SCAA has committed that, as the lexicon is updated, the wheel will be too.

world coffee research lexicon specialty coffee

“If you believe there is an attribute missing from this lexicon (these are the flavors, aromas, and mouthfeels), we invite you to submit it for consideration…”

In the end, I applaud the incredible work done on this new flavor wheel. It may not be finished, and it may not be perfect, but it is still a scientifically rigorous attempt to provide a vocabulary for coffee. And we can all contribute to its evolution.

To learn how to propose a new attribute or a new or revised reference, read here.

Perfect Daily Grind.