Ultrasonic Treatment with Gas Purging as a Quick Aging Treatment for Wine

Abstract

Previous generally favorable but conflicting reports of the effectiveness of quick aging treatments with ultrasound have been clarified by further experiments. Detailed sensory and chemical analyses are reported on five types of wine treated with hydrogen peroxide and with nitrogen, hydrogen, carbon dioxide, air, and oxygen, alone and combined with ultrasound. Definite effects were produced, yet the wines could not be considered overtreated. At least under the conditions tested, the effects of ultrasound do not appear promising as a quick means of improving wine quality. Acceleration of oxidation by ultrasound in the presence of air or oxygen was demonstrated. However, in at least some samples, a readily detected odor and flavor difference was produced by the ultrasound treatment in all of the wine types and with every gas. In a majority of cases, this difference was described as a scorched flavor.

Although this special flavor introduced by ultrasound was not highly unpleasant, at least at the levels produced here, overall quality scores were generally slightly lowered, complexity or richness of flavor not appreciably improved, and other factors (such as grape aroma) unfavorably affected by ultrasound.

Hydrogen produced a very low redox potential in wine without also producing bottle bouquet, proving that no direct cause-and-effect relation exists between the two. Otherwise, hydrogen, nitrogen, and (except for solubility) carbon dioxide appeared rather inert toward wine. Air and oxygen produced changes attributable to oxidation. Ultrasound accelerated this oxidation, and, for studying the chemistry of such reactions, may have some uses. Since the flavor changes produced in wine by ultrasound appear to require fairly prolonged treatment, other applications, such as aiding in degassing or facilitating extraction from oak wood, may be worth investigation for possible use in wine processing.