Acceleration of the Aging Process in Coffee Liqueur by Ultrasonic Wave Treatment

Coffee liqueur made from rice wine base was treated by ultrasonic wave for accelerating the aging process. After the coffee liqueur was treated by ultrasonic wave for 6 h, the color was able to reach the level of conventionally aged coffee liqueur at 120 days, as well as being able to maintain a high degree of lightness. The alcohol content, caffeine content and turbidity were found similar with 180 days of conventional aging; the content of main volatile compounds viz. butanol, isoamyl alcohol, ethyl hexanoate and ethyl lactate achieved the similar level as well as furan methanol content which achieved 89.2% of furan methanol level in conventional aging for 180 days. The aroma and taste are similar to the results of conventional aging for 180 days. Ultrasonic wave treatment is a good alternative for rice‐wine‐based coffee liqueur to shorten the duration of aging. Practical Applications Aging is one of the most important processes to improve the quality of wine, spirit and alcoholic beverage. Complex chemical reactions involving sugars, acids and phenolic compounds can alter the aroma, color, mouthfeel and taste in a way that may be more pleasing to the taster during aging. In conventional aging, coffee liqueur takes at least 6 months to reach the quality marketable level. It would be desirable to be able to accelerate this process, so that the same character of coffee liqueur could be produced in a much shorter time period. The ultrasonic wave treatment provided a method of aging that resulted in coffee liqueur that is aged as short as 6 h having the character conventionally achieved only after 6 months of aging. This study provides a useful method to reduce the aging time of coffee liqueur for producers.