If you put a bottle of vodka in your freezer, the liquid thickens, but it won't turn solid. Why doesn't vodka freeze when you put it in the freezer? The answer to the question has to do with the chemical composition of vodka and a phenomenon known as freezing point depression.
The Chemical Composition of Vodka
Mendeleev, the chemist who devised the periodic table, standardized the amount of ethyl alcohol (ethanol) in vodka when he was the Director of the Russian Bureau of Standards. Russian vodka is 40% ethanol and 60% water by volume (80 proof). Vodka from other countries may range from 35% to 50% ethanol by volume. All of these values are alcoholic enough to significantly affect the temperature at which the liquid freezes. If it was pure water, it would freeze at 0 °C or 32 °F. If vodka was pure or absolute alcohol, it would freeze at -114 °C or -173 °F. The freezing point of the mixture is an intermediate value.
Ethanol and Freezing Point Depression
When you dissolve any liquid in water, you lower the freezing point of the water.