The flavor of a cup of coffee is the result of a long chain of chemical transformations from the seed to the cup. Aroma precursors and volatile compounds are made and/or transported in the tissue of coffee seeds as the seeds grow and mature. The compounds and metabolites that accumulate during seed development contribute directly or through roasting-induced chemical reactions to the broad spectrum of aromas and flavors in the final cup. These precursors have both genetic and environmental determinant, and they influence both the sensory perception of coffee and the corresponding value that coffee buyers place on it. In order to rigorously improve coffee quality through breeding, it is essential to begin to understand the connections between genetics, the environment, chemistry, sensory perception, and preference/liking.
World Coffee Research is undertaking multiple studies that examine flavor volatiles and their chemical precursors in coffee, seeking to understand the determinants of key sensory/quality attributes in order to improve coffee quality through breeding.
Each project combines multidimentional analysis of large groups of coffee samples, including industry evaluation for feedback on the relative perception of quality of samples, sensory descriptive analysis to identify key flavor/aroma/sensory attributes using the World Coffee Research Sensory Lexicon, green/roasted coffee chemistry, and molecular genetics. Statistical analyses are used to identify correlations between quality perception, sensory attributes, chemistry, and the plant’s genetics. (And, in the case of the “unlocking coffee’s flavor code” study, the GxE interaction.)
Understanding the genetic basis of coffee quality will assist coffee breeders to make quality improvement a primary target of breeding programs, and will produce knowledge that significantly shifts our understanding of the determinants of quality.