It's not really enhancing your voice at all. I'll keep it simple. Basically, alcohol is a depressant, and drinking it just impairs your muscle co-ordination in your vocal folds. Which gives the effect as you described. Plus, it kinda numbs it at the same time, so you're unaware of how much output you're making relative to what you think you're singing like.
And no there isnt, i wouldnt drink alcohol before singing if i were you. Unless you dont want to again.