Some ice cream recipes call for alcohol to lower the freezing temperature and to add flavor. We have chosen not to because we don’t drink alcohol, don’t like the taste of alcohol and we can adjust the freezing temperature by adjusting the amount of sugar.
If you do add alcohol, be careful not to add too much. The alcohol, like sugar, acts as an antifreeze, lowering the freezing temperature of the ice cream. If there is too much alcohol, the ice cream never freezes and stays slushy. Often a teaspoon or two of alcohol can change the freezing temperature dramatically. This can happen even with regular flavorings like peppermint or vanilla that are dissolved in alcohol if you add too much. If your ice cream won’t freeze, try using less alcohol, possibly by using a more concentrated flavor extract.