When red wines are tilted in a glass wine sampler and observed in strong light against a neutral background, the thinner parts appear a shorter wavelength red than the thicker ones. It is discussed whether these hue-shifts, associated with thickness changes, are attributable to simultaneous contrast effects (Bezold-Brucke and Abney effects) or can be detected by, conventional instrumental color measurement by spectroradiometer or spectrophotometer (assuming Bouguer's law). The reported hue-shifts at different thicknesses appear to be attributable to both physical-chemical changes and contrast effects. This discussion is in three parts: (1) Color variability of wine in a glass and general comments on contrast effects by Ralph W. Pridmore, (2) Color coordinates of wine samples with different thicknesses by Rafael Huertas, Manuel Melgosa, and Angel L Negueruela, and (3) Final Comment by Ralph W. Pridmore. (C) 2005 Wiley Periodicals, Inc. Col Res Appl, 30, 146-152, 2005.