system
Given the following post, respond as if you're commenting on Reddit:
human
Why does powdered sugar taste different from granulated sugar?

Is it just beacuse one has more sugar molecules per cubic unit or does it have something to do with our taste buds?
gpt
Although taste is highly subjective, what you're perceiving may be the 3-5% cornstarch or tricalcium phosphate frequently added as an anti-caking agent, or simply the texture difference.  

Try grinding regular granulated sugar with a coffee grinder or mortar and pestle and taste-test that, the regular granulated sugar, and some store bought powdered sugar.  That may shed more light on your perceptions.  Powdered sugar should be chemically the same as granulated sugar, the only change is the size / shape of the particles and the resulting change in texture.