system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What is aftertaste and why is it so different than the taste while the food or drink is in the mouth?
gpt
Aftertaste is literally the taste of the food components after the food or drink is gone. Even after you've swallowed, flavor molecules will remain dissolved in your saliva or stuck to your tongue or inside of your mouth. When you swallow, only the flavors good at persisting will hang around, giving you an aftertaste that is different from the flavor of the food. For example, some common bitter tasting compounds can get inside the flavor detecting tongue cells and activate bitter taste sensations from there. Because they get inside taste cells they remain after you've swallowed and give a bitter aftertaste.