With interest in Robusta continuing to rise, a new flavour wheel has been developed to provide a descriptive tool for the evaluation of the often-under-appreciated species.
For years, the Specialty Coffee Association’s Coffee Taster’s Flavour Wheel has been a badge of honour displayed in roasteries and cafés across the world. The iconic illustrative chart, originally developed in 1995, has become a symbol of the specialty coffee scene as well as a tool to help tasters and roasters describe the kaleidoscope of flavours in Arabica coffees.
Yet, despite the Coffee Taster’s Flavor Wheel’s popularity and widespread use, Arabica’s close cousin, Robusta, didn’t have a comparable descriptive tool of its own – until now. In the early 1990s, Robusta accounted for about 28 per cent of global coffee production, but that’s now climbed to almost 44 per cent.
As climate change hampers Arabica harvests globally, many producers are turning to Robusta which thrives in hotter, more humid, and lower elevation environments. The rise can also be attributed to the growth of the Vietnamese coffee industry, which is an ideal origin for the species.
With production rates of Canephora (Robusta is a variety of the Canephora species) growing every year, a team of researchers led by Dr Fabiana Carvalho of the University of Campinas in Brazil determined it was time to develop a Coffee Canephora Flavour Wheel.
“The initial motivation came from the realisation that coffee graders in the specialty coffee market were struggling to assess the quality of specialty Canephora species,” says Dr Carvalho.
“This insight emerged during a comprehensive online course we hosted during the pandemic, which attracted coffee graders from around the globe.
“The course featured two cupping sessions of both low-grade and specialty Canephora samples. It became evident these graders had difficulty articulating the attributes of high-quality Canephora coffees.”
The difficulty was so pronounced, in fact, that one of the participants later reached out to Dr Carvalho to express surprise at how he scored a specific sample.
“I received an email from one of the participants, a grader from Japan. He shared his thought process during the sensory evaluation and expressed his astonishment at a specific sample he absolutely loved, yet he ultimately scored it as non-specialty,” she says.
“The grader noted the sample had umami and woody notes. He had learned to classify these flavours as off-notes, which led him to give the coffee a low score.”
To produce a flavour wheel to be used as a descriptive tool for evaluating the sensory qualities of Canephora, Dr Carvalho and her research team undertook a study to identify the aroma and flavour descriptors of the species. To do this, they recruited a team of 49 professional coffee graders from Brazil and Europe to represent exporting and importing regions.
In three cupping sessions, the graders tasted 67 samples of varying qualities from 13 different countries of origin that had been subject to multiple post-harvest processes. To assess the overall aroma, flavour, body, and aftertaste, as well as the final quality score, the graders used the Rate-All-That-Applies list in combination with the Coffee Quality Institute standard cupping protocol.
From this methodology, the group detected 202 descriptors that were then whittled down to 103 to create the three-tiered Coffee Canephora Flavour Wheel. This reduction was largely due to merging of terms, such as butterscotch, fudge, and toffee being merged with caramel. Likewise, fruit varieties were condensed to general fruit names, such as cantaloupe and honeydew being listed under melon.
Dr Carvalho says the identification of those 202 descriptors showcased just how different Canephora’s profile is to Arabica.
“Having a look into the SCA’s Coffee Taster’s Flavour Wheel, I found out the lexicon on which it had been developed used 105 coffee samples of specialty and low-grade coffees, but only low-grade Robusta was used. Thus, any positive aroma and taste of Canephora coffees have not been represented in the coffee lexicon nor in the most recent version of the flavour wheel,” says Dr Carvalho.
“It is basically a flavour wheel developed from and for Arabica coffees. Attempting to fit a Canephora coffee into the Arabica framework is difficult simply because it does not align.”
She uses the analogy of referring to the differences between white and red wines, with Arabica perceived as ‘more delicate’ and Canephora as ‘deeper’.
“A white wine flavour wheel, which presents the positive and negative attributes for white wines, is not an appropriate tool for the evaluation of red wines,” Dr Carvalho says.
“High tannin, high woody, and high brown spicy notes are positive for red wines, but negative for white wines.”
In line with the Coffee Taster’s Flavour Wheel, the descriptive terms in this new wheel are organised in hierarchical categories. Tier one features broader flavour categories such as fruity, tier two features more detailed subcategories such as stone fruit, and tier three features the most specific descriptors such as plum. Dr Carvalho and team hope the wheel can be used as a tool to “identify, understand, and map the sensory characteristics of Canephora”.
They believe standardising the terms used to describe the aromas and flavours of the species will not only benefit the coffee industry but also scientists working to improve quality.
“Historically, Canephora has been less valued than Arabica for being mistakenly considered to be a worse product in terms of quality, forcing it towards highly commoditised markets. This assumption of low quality has deflected the capture of Canephora by alternative supply chain mechanisms and weakened the motivation for quality improvements,” she says.
“The flavour wheel was developed to simplify and standardise the description of Canephora coffees. As a descriptive tool it can be used to identify, understand, and map the sensory characteristics of Canephora that are most important or valued in different markets. The standardisation in the descriptive analysis is important not only for the coffee industry, but also for scientists working on quality improvement.”
The research team are also hopeful that the development of the Coffee Canephora Flavour Wheel can continue to highlight quality Robusta coffees.
“Canephora has not even been referred to as ‘specialty’. The division has been so remarkable that when referring to high-quality coffee, the term ‘specialty’ specifically concerns Arabica,” says Dr Carvalho.
“I believe opinions are shifting. Research has shown Canephora grown in different terroirs and subjected to controlled postharvest fermentation processes can achieve improved cup quality. These findings suggest opportunities for sensory profile diversification and the potential for acceptance and recognition of Canephora in the specialty coffee market.
“It is crucial for graders to understand there is a market for specialty Canephora. The flavour wheel aids in facilitating communication among the various players involved in coffee production and trading.”
Now the new flavour wheel has been developed, Dr Carvalho hopes Canephora will no longer be in Arabica’s shadow. Yet, her research into the species doesn’t stop here.
“The expansion of flavour wheel research is its application to understand different markets and how to promote specialty Canephora,” says Dr Carvalho.
“It is very important to narrow the gap between the industry standards and consumer demand for Canephora coffees.
“Our future research will definitely include consumer testing to characterise the consumer’s sensory vocabulary, as well as understand acceptance and preference.”
This article was first published in the July/August 2025 edition of Global Coffee Report. Read more HERE.
