Study of the effect of organic acids on the crystal stability of wines

Abstract

The loss of solubility of tartaric acid salts of potassium and calcium is the reason for precipitation of crystal sediment in wine. The aim of this work was to study the morphological characteristics of crystal sediment of wines obtained by varying the acidic complex of the must using different technological methods. The approach of must de-oxidation, as well as the introduction of citric acid, provided a decrease in the temperature of saturation with calcium tartrate by 5.8-11.3 °C. At the same time, when introducing the tartaric acid, an inverse relation was noted - the indicator value increased by 34%. According to the results of the study, the relationship between quantitative content of potassium and calcium ions and temperature of saturation with potassium bitartrate (Tsat (KHTar) and calcium tartrate Tsat (CaTar)) was not established (r = -0.48 and 0.50, respectively). It was shown that acidifying of the must with 1 g/l of tartaric acid provided the formation of very large crystals of calcium tartrate, and 2 g/l of tartaric acid - a stabilizing effect for young wine by the end of the experiment. Regardless the method of varying acid composition of the must, the value of Tsat (KHTar) was in the range of 14.8-19.5 oC. The obtained results are intended to prove the necessity of preventive measures in wine production to ensure their crystal stability.