Groundbreaking Research in the Science of Flavor

by Caitlin McCarthy-Garcia

The coffee industry was built on exploration and discovery. Continuous innovations in coffee lead to advancements in growing, roasting, evaluating and brewing tastier coffee. The boundaries of quality are constantly being tested and pushed. New research in the field of sensory science, presented at the Specialty Coffee Association’s Symposium, will redefine how we describe quality.

This past April, one of the most interesting discussions at Symposium centered on the science of flavor. Flavor is the fundamental decider of quality in specialty coffee. In order to improve communication regarding quality, the industry requires a true standardization of terms. The sensory scientists at Kansas State University and Texas A&M University, some of the most recognized in the world, have partnered with World Coffee Research to develop a lexicon of terms that describe these flavors.  The lexicon will complement tools we coffee professionals already use to evaluate taste, including the Flavor Wheel and Le Nez du Café.

Researchers have discovered a total of 108 distinct flavor attributes found in coffee. They’re developing a manual that describes flavor attributes and a set of corresponding chemical references, with instructions on how to prepare them.

The lexicon will be an evolving document that is updated regularly with input from the industry. Coffee cuppers will have the opportunity to send in samples that contain an attribute that they think should be added to the list. A group of trained sensory advisers will then review the suggestion to check on its validity in coffee.

On a side note, both salt and apricot descriptors are not included in the lexicon- the sensory advisers felt these attributes are not truly present in coffee.

At the Roasters Guild Retreat in August, the coffee lexicon was put to the test. A sensory scientist from Texas A&M University led a group of 40 attendees through the process of becoming familiar with eight references, followed by scoring five samples of coffee. We tasted references of varying strengths of flavor attributes including bitter, sour, burnt, roasted and balanced. Then we scored five brewed coffees on a 0-15 point scale of intensity. At first attempt with the lexicon, references were effective and calibration was a successful learning experience.

One of the greatest challenges for the industry at large is to describe quality and have it translate across the supply chain. The purpose of the coffee flavor lexicon is to have a sensory diagnostic tool that quantifies coffee descriptors. The hope is that by developing a common set of flavor descriptors, we can more easily recognize and reward quality, from farmer to consumer. Researchers will publish the lexicon online by end of year.