Views:4 Author:Anne Marie Helmenstine, Ph.D. Publish Time: 2020-06-29 Origin:ThoughtCo.
Why Vodka Doesn't Freeze in Most Home Freezers
By Anne Marie Helmenstine, Ph.D.
Updated August 18, 2019
People who drink vodka commonly keep it in the freezer. The vodka gets nice and cold, yet it doesn't freeze. Have you ever wondered why that is? Will the vodka ever freeze?
The Freezing Point of Vodka
Vodka consists primarily of water and ethanol (grain alcohol). Pure water has a freezing point of 0ºC or 32ºF, while pure ethanol has a freezing point of -114ºC or -173ºF. Because it's a combination of chemicals, vodka doesn't freeze at the same temperature as either water or alcohol.
Of course, vodka will freeze, but not at the temperature of an ordinary freezer. This is because vodka contains enough alcohol to lower the freezing point of water below the -17°C of your typical freezer. It's the same freezing point depression phenomenon that occurs when you put salt on an icy walk or antifreeze in your car. In the case of Russian vodka, which is standardized to 40% ethanol by volume, the freezing point of the water is lowered to -26.95° C or -16.51° F . That vodka might freeze outdoors over the course of a Siberian winter, and you can freeze it with an industrial freezer or using liquid nitrogen, but it will remain liquid in a normal freezer, which typically has a temperature no lower than –23ºC to – 18ºC (-9ºF to 0ºF). Other spirits behave the same way as vodka, so you could put your tequila, rum, or gin in the freezer with pretty much the same result.
Beer and wine will freeze in a home freezer because they contain much lower levels of alcohol than you'll find in distilled liquors. Beer is typically 4-6% alcohol (sometimes as high as 12%), while wine runs around 12-15 % alcohol by volume.
Using Freezing to Enrich the Alcohol Content of Vodka
One handy trick for increasing the alcohol percentage of vodka, particularly if it's lower in alcohol content than 40 proof, is to apply a technique known as freeze distillation. This can be achieved by pouring the vodka in an open container, such as a bowl, and placing it in the freezer. Once the liquid cools below the freezing point of water, one or more ice cubes may be added to the bowl. The ice cubes serve as crystallization nuclei, much like using a seed crystal to grow larger crystals for a science project. The free water in the vodka will crystallize (form ice), leaving behind a higher concentration of alcohol.
Storing Vodka in the Freezer
It's probably a good thing vodka doesn't ordinarily freeze in a freezer, because if it did, the water in the liquor would expand. The pressure from the expansion could be enough to shatter the container. This is a good point to keep in mind if you're considering adding water to vodka to freeze it out and increase proof. Don't overfill the bottle or it will break when the water freezes! If you do freeze an alcoholic beverage, choose a flexible plastic container to minimize the risk of accidents or breakage. For example, choose a bag similar to the type used for premixed frozen cocktails.