sour salt vs flavouring

sour salt and flavouring both are nouns.

Word	Noun	Adjective	Verb	Adverb
sour salt	Yes	No	No	No
flavouring	Yes	No	No	No

As nouns, flavouring is a hypernym of sour salt; that is, flavouring is a word with a broader meaning than sour salt:

Other hypernyms of sour salt include flavorer, flavoring, flavourer, seasoner, seasoning.

sour salt (noun)	flavouring (noun)
crystals of citric acid used as seasoning	something added to food primarily for the savor it imparts