I wouldn't know. I don't know what liquor smells like, 'cause I'm too young to drink it.
5 seconds sound clip from the Back to the Future Part II movie soundboard.
You can hear this line at 01:17:48.297 in the Blu-ray version of the movie.
Quote context
[...]
- Well, well, well, Mr. Tannen. How nice to see you here.
- Why, Mr. Strickland, it's nice to see you, sir.
- Is that liquor I smell, Tannen?
- I wouldn't know. I don't know what liquor smells like, 'cause I'm too young to drink it.
- I see. And what have we here?
- Sports statistics, interesting subject.
- No, it ain't homework, 'cause I ain't at home.
- Marty, you're beginning to sound just like my mother.
[...]