When you put a pot of soup in the fridge and then eat it the next day, it tastes better. That’s because the molecules that produce flavor have had time to spread around the dish, becoming more pronounced and integrated, says Shirley Corriher, author of CookWise and BakeWise.
Time also allows enzymes that may be present in the food to convert starch to sugars, so potatoes or legumes may become sweeter, says Corriher. And flavors may also intensify when you reheat your food simply because more liquid has evaporated, creating a more concentrated end product.
It might also be you. The longer you smell something (and we all know how smell helps you taste), the less you notice the aromas; this is called olfactory adaptation. Dr. Marcia Pelchat, a sensory psychologist at the nonprofit research institute Monell, says: “If you are the chef and you are bending over a pot in the kitchen all day, you won’t be as sensitive to those aromatics as you might be the next day.”