system
Given the following post, respond as if you're commenting on Reddit:
human
If I take cheap 80 proof vodka and put it in the freezer, why doesn't part of it freeze so I can take that part out and make stronger vodka?

At what temperature does 80 proof vodka freeze? Is it:
0 - 80/200 * 110C = -44C? Why doesn't the water part freeze before the ethanol part, so I can take the ice cube out and make stronger vodka?

If I added a rough surface like a rock to the inside bottle, would that help the ice crystals get started?
gpt
Solutions don't work that way.  If you continued to cool the vodka, you would eventually reach a temperature where it did begin to freeze; however, the ice you ended up with would still contain both ethanol and water.  The concentration of the ethanol in the ice would be a little different than the concentration remaining in the liquid, but this would not be an efficient method to make stronger vodka.