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

Pasta sauce is known to bring out iron of iron-based pans, which tends to be slighly bitter and metallic tasting, though in tupperware nothing significant can leach. It might just be the melding of flavors. If you could taste additives to the plastic, you’d be getting a whole lot more than is allowed.