Adjustment ofpH in Cynthiana and Syrah wine using enological and ion-exchange methods

Cynthiana (Vitis aestivalis) and Syrah (Vitis vinifera) grapes are used to produce premium wines but can have high pH problems. Cynthiana wine also has a high titratable acidity (8.5 to 12 g/L tartaric acid) problem, which is uncommon in Syrah wine. High pH wine occurs in every grape-producing region of the country and ion-exchange technology provides a means of increasing quality. Ion exchange technology can especially benefit small wineries in their quest to produce premium wines since small wineries cannot store large quantities of wine for blending. Enological methods (pre- and post-fermentation) and ion-exchange technology (membranes and resins) were used to produce Cynthiana and Syrah wines with an optimum pH (3.5).; A high-performance liquid chromatography procedure was developed to determine organic acids, sugars, and ethanol content in Cynthiana and Syrah wines, and standard analyses were used to determine the effect on wine attributes. Enological methods were used to adjust the pH of Cynthiana and Syrah wines. Although pH was reduced using different enological methods, ion exchange was necessary to lower wine pH to an optimum range. Ion exchange with membranes and resins lowered the pH and potassium content and increased titratable acidity of wine without having detrimental effects on color and phenolics. Differences in wine attributes were attributed more to adjustment with membranes or resins rather than manufacturer. Sensory attributes of Cynthiana and Syrah wines were descriptively analyzed. Regardless of the enological method or ion exchange treatment used for pH reduction, wine quality decreased during storage.; These ion-exchange techniques have great commercial potential to enable winemakers to reduce pH without acid addition allowing for an alternative pH-reduction method. Although ion exchange was successful in decreasing wine pH, research should be done to further investigate the effects of pre- and post-fermentation treatments on pH reduction.