Alcohol can impact glucose in a variety of different ways, depending largely on the type of alcohol consumed and your current energy state. It likely comes with no surprise that higher carbohydrate beverages, such as cocktails or beer, can lead to an immediate rise in glucose. Other types of alcohol, such as liquor or dry wine, can result in a slight reduction in glucose or no effect at all afterwards.
While the occasional drink can lead to a minimal change in glucose in the moment, you may experience higher fasting glucose and overall glucose values the next day. Of course, chronic and excessive alcohol consumption can lead to a reduction of liver glycogen storage, effecting all organs of the body and impairing overall glucose tolerance.