I like the idea, but I think you could push a few things.
The sniffing and the "disgusted" part are a bit simple. I think you could push the acting in those areas in order to give him more character. It's a bit generic right now and given the long pause, it's a great opportunity to do something very character specific. It doesn't have to be something crazy, but just a specific, original way he sniffs it and reacts to it.
You could maybe also involve the bartender more. What if, after he puts down the last drink, he leaves his hand at the edge of the bar top, and then taps his finger(s), something that shows he's slightly annoyed, since the customer is taking so long.
What do you guys think?