Ethanol also called ethyl alcohol grain alcohol drinking alcohol or simply alcohol is a chemical compound a simple alcohol with the chemical formula C 2 H 6 O Its formula can be also written as CH 3 − CH 2 − OH or C 2 H 5 − OH an ethyl group linked to a hydroxyl group and is often abbreviated as EtOH Ethanol is a volatile flammable colorless liquid with a slight characteristic