USE OF CHEMICAL METHODS FOR TARTARIC STABILIZATION IN WHITE WINES

Tartaric instability is a natural phenomenon in the evolution of wines, mainly in white wines, in which tartaric acid salts reach a state of supersaturation, inducing the formation and growth of crystals and causing precipitation. The presence of precipitated crystals in the bottles can negatively affect the acceptance of the beverage by consumers, making it necessary to apply methods for preventive treatment to stabilize the wines. Chemical methods are based on the properties of protective colloids and work by shifting the thermodynamic equilibrium to prevent crystallization or promote dissociation. The aim of this study was to compare the effect of two tartaric stabilizers in white wines obtained from grapes produced in a vineyard with and without a cover crop and with two different irrigation rates. In order to prevent potassium bitartrate precipitation, different concentrations of carboxymethyl cellulose (4 and 2 mL/L) or a new enological compound prepared based on potassium polyaspartate (250 and 500 µL/L) were added to the white wines during bottling. The wines were stored at room temperature for 60 days. The stability of potassium bitartrate was determined using the mini-contact test and the saturation temperature test, with the assays performed in duplicate. After storage, samples of wines without stabilizer addition (control) remained unstable, with electrical conductivity variation (Δx) ranging from 64.8 to 158.5 µS/cm. On the other hand, all wines were stabilized after the addition of the enological adjuncts analyzed, in both tests performed. The use of the maximum concentration of potassium polyaspartate (KPA) showed lower values for Δx (15.8 to 26.30 µS/cm), and the lower the Δx, the greater the tartaric stability of the wine. It is concluded that the analyzed enological adjuncts stabilized the wines from a tartaric perspective, with KPA demonstrating greater efficiency compared to carboxymethyl cellulose.