First a little background...
Like all my jolly good fellows, I drink my whiskey clear,
I'm a ramblin' gamblin' helluvan' engineer!
College football fans may recognize that as the close of the Georgia Tech fight song. In addition to singing the entire fight song to my son each night I put him to bed, I use the last two lines as my guide to tasting whiskey. I will generally pour a glass neat (standard one to two finger depth) and have a taste. I can then adjust with either ice or water to open up the flavor or, in some cases, cool it down.
What is bourbon?
Bourbon is an American whiskey made primarily of corn. There are a lot of legal requirements a distiller must meet in order to call his whiskey bourbon. One of them is not that he/she be located in Bourbon County, Kentucky. This is a common urban legend.
Bourbon must be at least 51% corn and at least 80 proof (40% alcohol).
What other types of American whiskey are there?
Several. People are probably most familiar with Jack Daniels, which is a Tennessee Whiskey. Tennessee whiskey, which is just distilled in Tennessee, undergoes a filtering process in which the mash is run through a charcoal maple sugar.
In addition to Tennessee whiskey, there are ryes (51% rye), wheat whiskeys (51% wheat), corn whiskey (at least 80% corn) and a few others.