Relation of Type and Concentration of Phenolics to the Color and Stability of Rosé wines

Rose wines that are prepared by blending red table wines with white or by a short period of fermenting red must with the skins are claimed to be less stable than Roses prepared from Grenache or Gamay grapes. Difference in stability between blended pink wine and true roses may be due to differences in kind and concentration of anthocyanin pigments and in the phenolics and cations present. The role of changes in phenolic and anthocyanin composition during accelerated storage deterioration on rose and base wines was studied. Objective color measurements by spectrophotometric and thin-layer colorimetric techniques were run concurrently to determine the relationship of color changes on deteriorative storage with changes in chemical composition. The vanillin-reactive flavonols decreased with increase in storage temperature, and the loss of flavonols paralleled the destruction of anthocyanin pigments. The objective color measurements can be used as sensitive indicators of anthocyanin destruction as well as of the occurrence of the browning reaction. A comparison of the results from the two methods of measuring color of wine substantiates the usefulness of the rapid thin-layer colorimetric method developed in this laboratory.