Variation of volatile organic acids in spirits during storage at low and room temperatures

Abstract

The volatile organic acids are formed during storage of the spirit under inadequate conditions and their presence in the marc distillate has a negative influence on its sensorial characteristics. The object of refining marc distillates is to improve their sensorial characteristics. In this study, this process was carried out on a distillate of grape pomace that was maintained for 7 mo at two temperatures (cold at 5 °C and at room temperature, 25 °C) in order to understand the influence of both the parameters (time and temperature) on the volatile acids content. For the concentration of the volatile acids, solid-phase-extraction (SPE) was employed as the stage previous to determination by gas chromatography. The results of the analysis indicate that, in general, the concentration of the organic acids tends to decline during the refining period, this decline being more important after the fourth month. This decrease is especially important with regard to the acetic acid, due to which the refining process is beneficial, because this is the major distillated acid. With regard to temperature, no significant differences have been found in the comportment of the acids.