Examining the case of green coffee to illustrate the limitations of grading systems/expert tasters in sensory evaluation for quality control

Grading systems since their conception have aimed at facilitating commercialisation of food stuff world-wide. However, while many food products can have their quality assessed by analytical means, there are many foods that are sold according to their sensory quality and for which quality is not easily measured by conventional analytical techniques. Measuring sensory quality in some products has moved forward and utilises fully trained panels to set-up quality control systems and routine evaluations while others still rely on traditional commercial classifications and grading systems. The grading discussed here must be differentiated from grading using "trained experts" to evaluate food products according to legislated standards. There are specific cases in which the need to comply with national or international standards requires the development of specially trained tasting experts. Bisogni, Ryan, and Regenstein (1987) [In D. E. Kramer, & J. Liston (Eds.), Seafood quality determination (p. 547). Amsterdam: Elsevier Science] illustrates quite well this specific scenario. The case of coffee, the most traded agricultural crop world-wide is examined here. In coffee a high diversity of classification systems is applied and the use of the "expert cupper" is the norm. There is not a unique and universal system applied world-wide for the quality control of green coffee. Tailor made procedures are selectively implemented by International, National, local bodies, trading institutions and private companies. Procedures are mostly geared to facilitate the trading of the commodity and sensory quality is in most cases described by "cuppers" or "liquorers" using personal opinion and tasting experience accumulated over the years. (C) 2002 Elsevier Science Ltd. All rights reserved.