How much drinking alcohol must be added to water keep it from freezing?

Adding alcohol to water will not prevent it from freezing. In fact, alcohol has a lower freezing point than water, meaning that it will freeze before water. The freezing point of a mixture of water and alcohol depends on the concentration of alcohol. The more alcohol that is added, the lower the freezing point of the mixture will be. However, even a high concentration of alcohol will not be enough to prevent water from freezing at temperatures below -18 degrees Celsius (0 degrees Fahrenheit).