Hi there Rob....
Could it be that the acid has worked on the trap door, but you can't go into the cellar because someone will see you? The owner's wife may be down there stocking shelves? If so, you need to go back up into the liquor store and talk to the owner again.
I don't remember the details too well here, but if you are convinced you used the acid in the wrong place, probably would be a good idea to go back to a save game.