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

Another thing I thought of. It could be burnt fronthw sides of the pan. Like if you scrape the pan when you put the left overs away, the stuff you scrape from the sides could be giving the bitter flavor. That is if there’s a lot stuck on and you do scrape the sides.