Characterizing wine finish using TCATA product contrails
Wine quality is associated with the pleasantness of flavours, tastes, and mouthfeels that linger and evolve after swallowing. In a designed experiment, Baker et al. (submitted) started with musts with different initial sugar contents (21 and 27 °Brix) to produce two wines varying in ethanol content, Low and High, with 10 and 15.5% v/v, respectively. A third wine, Low-to-high, was then obtained by manipulating the Low wine post-production such that its ethanol concentration matched the High wine. Sensory aspects of the finishes of the three red wine treatments were characterized by trained panelists using Temporal Check-All-That-Apply (TCATA) methodology. For subsequent analyses, data were discretized into beginning, middle, and end segments.
Previously TCATA product trajectories have been proposed to visualize the evolution of sensory properties of each product over time (Castura et al., 2014, submitted).
As a novel development, we introduce TCATA product contrails. Multivariate data analysis is conducted to obtain a sensory space and product trajectories. Then, with axes fixed, bootstrap resampling is conducted to investigate the uncertainty of the points along the product trajectories. Here, product contrails are presented for TCATA wine finish data via PCA biplot visualization, both at specific time slices, and in animation, showing the evolution of the wine finishes. Interpretations derived from TCATA product contrails permit a more nuanced investigation of continuous temporal sensory data and of the uncertainty surrounding the product trajectories. Results broadly support conclusions obtained from discretized data, and highlight important relationships between ethanol level and wine finish perception.
Castura, J. C., Baker, A. K., & Ross, C. F. (2015). Characterizing wine finish using TCATA product contrails. 1st Afrosense Conference. 23-26 November. Stellenbosch, South Africa.