The Coffee Science Foundation (CSF) and University of California, Davis are joining forces to launch a new research project that aims to determine detection thresholds for relevant physical defects in green coffee.
The research will take place at the UC Davis Coffee Center in California, United States, and will focus on identifying and understanding the sensory impact of physical defects in green coffee samples from Brazil and Guatemala.
Traditionally, the quality of green coffee has been evaluated using a scoring system based on visible defects in a sample. Grading systems, including the SCA Green Coffee Classification, assign “full defect equivalents” to various defect types. Yet, the team behind the research say these classifications are based more in tradition than sensory science, and that the actual sensory impact of different defects on final cup quality has yet to be fully examined.
“Coffee today is scored by exacting physical defect standards, but there is little understanding of how those standards were actually developed historically. For example, why are five chipped beans judged to be equivalent to one fully black bean? Why not four or six?” says William Ristenpart, Director at the UC Davis Coffee Center.
“We are excited because we think our research will help develop a rigorous and quantitative basis for green coffee defect standards.”
This study aims to bridge the gap by determining detection thresholds for physical defects in both Arabica and Robusta green coffee. The research will analyse how different defects, such as partial black beans, chipped/broken beans, and minor insect damage, impact the sensory qualities of brewed coffee.
As part of the study, a panel of coffee-drinking consumers will identify the impact of these defects. They will provide insight into whether the numerical equivalencies historically assigned to these defects correlate with their actual sensory effects detectable by consumers.
The research team believe that by understanding the thresholds at which physical defects become detectable in brewed coffee, this research has the potential to refine coffee grading practice.
“The UC Davis Coffee Center has extensive experience in both post-harvest processing and sensory detection, which are the key disciplines relevant to this research”, says Peter Giuliano, Executive Director of the Coffee Science Foundation.
“We are excited to partner with them on this potentially transformative research.”
The Coffee Science Foundation (CSF) is a support organisation of the Specialty Coffee Association (SCA) that serves as the research arm of the SCA.
