Effectiveness of the 'Mouth-feel Wheel' for the evaluation of astringent subqualities in British Columbia red wines
This research examined the effectiveness of the 'mouth-feel wheel' for the assessment of astringent subqualities in 25 commercial British Columbia (BC) red wines. Twelve judges discussed, adapted and practised the definitions and reference standards (fabrics) to characterise the astringent subqualities. The astringent qualities were organised into six categories (surface smoothness, drying, dynamic, weight, complex ripe/integrated, unripe/unintegrated), each consisting of specific descriptors or subqualities (3≤n≤7), as outlined in the literature. The wines were evaluated in duplicate using a strict tasting protocol. Judges rated the magnitude of astringency and aftertaste and identified the astringent subqualities using a check-off system. The subquality frequencies were weakly correlated (r=0.40) with the astringent and aftertaste intensities. Judge consistency and overall performance were examined using chi-square and principal component analysis (PCA); in general, judge consistency was poor, both within and between judges. The interrelationship of the astringent subqualities was explored using multidimensional scaling and PCA, employing distance and correlation matrices, respectively. Both techniques showed that the descriptors successfully identified different levels of astringency. However, the close location of some of the descriptors suggested that some judges may have been using different vocabularies to describe the same astringent subqualities. It was believed that the lexicon describing the astringent subqualities would need simplification and clarification before it could be used effectively to describe BC red wines.