Mouths water immediately.

Meaning: This means that the mouths of the people who are smelling the pleasant food smells are producing saliva or water right away, which is a natural response to the smell of food.

Choice of Words: Mouths are the opening in the face through which food is taken in. Water is a liquid that humans and animals need to drink to stay alive. Immediately is an adverb that means without any delay or right away.

Alternative Expressions

Related Expressions