Distillation by freezing

Hey guys!

I assume we all know how distillation works: You use the different boiling points of liquids to separate a mixture of them. I have a bottle of vodka in the freezer and was wondering why not the same is happpening in this case: The water should freeze and the alcohol should stay liquid... Ideas?

>>1
The water traps the ethanol as it freezes, making it look like there's only ice. You can't really tell unless you look closely.