The Coffee Taster’s Flavor Wheel: The Past, Present, & Future of Tasting Coffee

Whenever Covoya Coffee hosts a cupping, there are a variety of words heard around the cupping tables as people try to describe what they smell and taste. Words that you won’t hear are: “De gustibus non est disputandum,” though some people may be thinking them, albeit in English rather than Latin: “There is no accounting for taste.” That is, taste is subjective; personal.

But according to World Coffee Research (WCR) and the Specialty Coffee Association (SCA), there actually is accounting for taste via the Sensory Lexicon and its companion, the Coffee Taster's Flavor Wheel. 

You are very likely familiar with the coffee wheel known as the Coffee Taster's Flavor Wheel, versions of which hang in cupping rooms all over the world. First introduced by SCA(A) in 1995, the coffee flavor wheel was completely reinvented, hub to spokes, in 2016. What you may be less familiar with is how the new coffee flavor wheel is based on crazy-serious research done by WCR, research that led to the publication of the Sensory Lexicon, currently available in version 2.0. 

What’s the big deal? To put it as simply as possible, nothing compares to the WRC Sensory Lexicon, not even close.

The History of The Coffee Flavor Wheel & The Sensory Lexicon 

We’ve lived with lists of flavor attributes in coffee for a long time. In the 1922 edition of All About Coffee, by WH Ukers, the back pages contain a bibliography and an index. The 1935 edition added a “Coffee Dictionary.” Within the dictionary are seven taste descriptors. But within the definition for “Cup Testing,” there are an additional 10 taste descriptors. Ukers documents — but doesn’t always define — 17 words used to describe flavors in coffee in his dictionary alone.

The practice of cupping was going through one period of standardization around the time Ukers was preparing his new edition, so it’s no surprise we find taste descriptors added to his glossary. It’s also no surprise that at least 13 of the 17 are negative descriptors, and only two of the remaining four, “Acidy” and “Rich,” are positive (and it could be argued that “rich” was more of a reference to mouthfeel). The other two, “Mellow” and “Neutral,” are, well, neutral. Back then, and for another 50 years at least, the primary focus of cupping was to detect defects. Secondary to defect detection was finding what they called “styles,” what we call profiles, as substitute components for blends. Virtually all roasted coffee was blended. 

Of Uker’s 17 taste descriptors, six have survived these 90 years and appear on the newest SCA coffee flavor wheel: 

• 1) Musty
• 2) Woody
• 3) Winey
• 4) Rubber
• 5) Bitter
• 6) Sour

Three more live on in spirit if not the exact word: earthy for groundy, animalic for hidey, and a few sections of the green/vegetative part of the wheel have replaced the once all-encompassing “grassy.” Not too bad. Arguably, half of Ukers’s taste descriptors have survived a test of not only time, but hard-core science. 

Nevertheless, consistent and wide spread use of a word by the coffee trade over decades did not solve the fundamental challenge of talking about taste, a challenge made especially acute when dollars are riding on the words that we use. I may know what I mean when I say “honey-like,” but I’m not sure I know what you mean when you say “honey-like.” And when you say, “butterscotch candy, but only the kind my grandma always had in a jar next to the toaster,” well, I’ll just take your word for it.

But imagine and what if, when I said honey and you said honey, we were both thinking about one tablespoon of Busy Bee Pure Clover Honey dissolved in 250 milliliters of hot water and served in a 1-ounce cup (covered with a plastic lid)? And what if, when I say grapefruit and you say grapefruit, we both mean Ocean Spray 100% White Grapefruit Juice? Because, before, I was thinking of grapefruit juice and you were thinking of that grapefruit you had at breakfast a few weeks ago, probably at your grandma’s house. 

That, in a nutshell (or 1 tablespoon of chopped Diamond Star shelled walnuts in a medium snifter for “woody” aroma), is a large part of what the WCR Sensory Lexicon does. Let’s stretch out an analogy as thin as possible to make the point.

Think of a cowboy. Do you have a good image of a cowboy in your head? Good, me too. Now we both can tell a story about the cowboy — except, we can’t. My cowboy is Woody from Toy Story. Your cowboy is Clint Eastwood in The Good, The Bad, and The Ugly. The Sensory Lexicon says, “listen-up folks, the cowboy is actually Robert Redford as the Sundance Kid.” Well, of course. 

If you’ve ever been a part of cupping calibration, whether it be among your own team, as part of some competition judging panel, or with customers or suppliers, it can sometimes seem like a cupping negotiation. I mean, if my idea of a cowboy is Woody and yours is Clint Eastwood, we’re pretty far apart and there is no world in which Clint Eastwood is cool enough to hang with Woody. Add to this the fact that the only way we can express what we think a cowboy looks like is by drawing a picture.

I promise to stop stretching this analogy eventually, but to cap it off, the WCR Sensory Lexicon not only says the cowboy is Robert Redford but holds up a high-resolution photograph of Redford as the Sundance Kid so we’re all picturing him at the same age wearing the same outfit and riding the same horse (just in case someone was, you know, picturing him as the The Electric Horseman on the horse with all the light — you know who you are). 

We both taste vanilla, and we’re both thinking of vanilla ice cream, but you’re thinking Jeni’s Ndali Estate Vanilla Bean ice cream and I’m thinking of good ‘ol’ Ben & Jerry’s Vanilla.  The Sensory Lexicon holds up a high-resolution photo and says it’s “1/8 teaspoon of McCormick Pure Vanilla Extract Stirred into ½ cup of whole milk and serve in a 1-ounce cup.” 

How The Sensory Lexicon Was Created 

But just as important as providing this sort of universal calibration tool and refining our “common language” is how and why the Sensory Lexicon was created.

With the help of the Lexicon, the day may come when we are all saying what we mean and knowing what we say while cupping coffee, but the lab coats (sensory scientists at Kansas State University, Texas A & M, and UC Davis) that developed the Lexicon did it for the scientists first. For researchers who are trying, for example, to improve the climate resilience of a particular coffee without sacrificing—or while improving on—positive and notable flavor attributes, it is critical that they are all using the same language and picturing the same cowboy (I know, I’m sorry).

The goal of the World Coffee Research Sensory Lexicon is to use for the first time the tools and technologies of sensory science to understand and name coffee’s primary sensory qualities, and to create a replicable way of measuring those qualities. – Introduction to WCR Sensory Lexicon 

There are three crucial elements to the World Coffee Research Sensory Lexicon:

1) Descriptive: It is purely a descriptive tool, which allows you to say with a high degree of confidence that a coffee tastes or smells like X, Y, or Z. and does not provide for quality evaluations.

2) Quantifiable: It provides a measurement of intensities. This allows us to compare differences among coffees with a significantly higher degree of precision.

Replicable: If the system is used properly, no matter how different two evaluators are, they will have the same results. An evaluator in Texas will get 'blueberry, flavor: 4' just the same as one in Bangalore.

So, we not only all know the cowboy is Robert Redford as the Sundance Kid, we all agree it is Robert Redford in Act II of Butch Cassidy & The Sundance Kid, when he looks down the mountain at the posse dust and says, “Who are those guys?”

Clearly, there is a great deal more to the World Coffee Research Sensory Lexicon than the development of taste and aroma references as common language and it is worthy of study for those who are serious about sensory skills and the necessity of calibration in coffee as a business. With help from sensory scientists and some of the finest palates in coffee, WCR also created common points of reference for mouthfeel, amplitude (how it all comes together), and a scale for intensity.

The Future of The Coffee Taster’s Flavor Wheel

The Sensory Lexicon is free to download and it won’t be long before it is required reading and required understanding for coffee buyers and sellers.Covoya has adopted 9 primary taste descriptors from the Sensory Lexicon and Coffee Flavor Wheel as search filters on our website. The Lexicon will not eliminate the poetry of our subjective experience (or marketing copy) when tasting coffee, but it can bring much needed structure and objective points of reference to business transactions dependent on taste.

¹Though the 1922 edition didn’t contain a glossary, Ukers used all the same words as taste descriptors throughout the body of the book, except for “rubbery,” which does not appear in the 1922 version. In both editions he occasionally uses a word that does not appear in his glossary and seems to be a synonymous with sharp acidity: “Tang.” Ukers does use the word "spicy" as a taste descriptor, but only once in 800 pages. "Sweet" only appears three times to describe black coffee. In one instances he uses the word "charred" to describe flavor. "Smoky" is used twice, both times in reference to coffees from Bahia.

²From the Abstract: "This study used a novel application of traditional sensory and statistical methods in order to reorganize the new coffee Sensory Lexicon developed by World Coffee Research and Kansas State Univ. into scientifically valid clusters and levels to prepare a new, updated flavor wheel. Seventy‐two experts participated in a modified online rapid free sorting activity (no tasting) to sort flavor attributes of the lexicon. The data from all participants were compiled and agglomeration hierarchical clustering was used to determine the clusters and levels of the flavor attributes, while multidimensional scaling was used to determine the positioning of the clusters around the Coffee Taster's Flavor Wheel. This resulted in a new flavor wheel for the coffee industry."

Cover image from scaa.org.