Here's why:
* Concrete nouns refer to things that are tangible and can be perceived by the senses. Desserts are real, physical things you can see, taste, and touch.
* Abstract nouns refer to ideas, qualities, concepts, or feelings that are not tangible. Examples include happiness, justice, love, and freedom.
While "dessert" itself can be a general concept, when you say "desserts," you are referring to a specific category of tangible food items.