This is a very, very basic western alcohol summary.

Most western alcohol is grain-based, from wheat, corn, potato and barley. Usually there are mixtures of any of these spirits, such as brandy or bourbon. Scotch, for example, is from malted barley. Malted barley is taking the barley seed and getting it to just sprout, then using it to make the mash that then ferments into alcohol. Scotch is ONLY malted barley, no corn alcohol, no wheat alcohol. Vodka is sometimes exclusive too, made from potato, wheat or even grapes. Other western liquors could contain any type of alcohol, mixed to produce specific flavors. Those flavors become bourbon, whiskey, etc. The key to all of these liquors is from a process called "distilling," where the alcohol is evaporated from the mixture called "wort," (similar to beer at this stage) and condensed with special equipment, collected, bottled and/or aged.