Ethanol is a highly polar substance. This is because the hydroxyl, or OH, group at the end of the ethanol molecule contains a polar bond.
Polar bonds create polar molecules. Polar bonds occur when two covalently bonded atoms unevenly share their electrons. This, in turn, results in an uneven distribution of the molecule's electrical charge, which means that at any given time, parts of that molecule carry a weak-positive or weak-negative charge. These weak-positive and weak-negative charges attract polar substances to one another, so polar substances can dissolve other polar substances. They also exclude non-polar substances, such as oils. A rudimentary but effective test for polarity is to see whether a substance dissolves in water, a common polar chemical. Since ethanol is commonly dissolved in water in alcoholic beverages, one can easily infer that it is a polar substance.