system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:Why does defrosted ice taste different (and worse) than water?
gpt
If your question is specific to ice cubes in the freezer, rather than lab conditions:  The ice in your freezer absorbs various smells over time....smells from the food, smells from the kitchen, smells from the likely dirty ice cube tray.    Or in the case of an ice machine, smells from it.     So, when that ice melts, it's some other stuff in there...not just water.  That's what you are tasting.