I just had some of my mom’s leftover spaghetti, and I realized that it always has a slightly more bitter taste in the morning after being reheated. What causes this kind of reaction?

Question

It happens both when stored in pyrex or tupperware.
Ingredients aren’t anything unusual; onions, garlic, hamburger, tomato paste, etc.
Tastes sweeter when fresh off of the stove, but has a more bitter taste when reheated as leftovers.

In: 159

Answer 1

If some of the sauce or other components are getting stuck to the bottom of the pan, you wouldn’t be getting that on a fresh serving. However if someone scrapes the bottom of the pan while putting it in containers, the burnt/bitter parts are now throughout the rest of the dish.