Here is what I got to know:
"Alcohol, like caffeine, dehydrates the body and thus the vocal folds. The condition of dehydrated vocal folds makes for an inferior singing instrument. In addition to the physiological problems inherent in alcohol, anything that distorts the mind or nervous system is going to impair the vocalist's ability to sing properly. An occasional glass of wine or cocktail will not destroy your voice, however drinking alcohol even a day or two prior to singing is absolutely a bad idea."
Say No TO ALCOHOLD NOW!