Understanding why all other whiskies cannot be called bourbon makes it easier to understand why certain whiskies can be. I talked about the legalities of "bourbon" here, and will explain how other whiskies are different.
To recap, "bourbon" must be:
- made with at least 51% corn,
- cannot be distilled at a proof higher than 160,
- cannot be barreled at higher than 125 proof,
- the aging must take place in fire-charred oak barrels,
- the barrels must be previously unused, and
- nothing can be added during the bottling other than water.
So what about all the other whiskies around?
Rye Whiskey essentially follows the guidelines of bourbon. The difference is that the grain used in its production must be at least 51% rye. Pretty simple difference. Rye brands include Wild Turkey Rye, Sazerac, Rittenhouse, Old Overholt, Jim Beam Rye, and Michters Rye to name a few.
Wheat Whiskey is, again, made per the bourbon formula with the exception that the majority of the grain must be wheat and not corn. Bernheim Original is an example of wheat whiskey, and comes from Heaven Hill Distilleries. To be honest, I've never tasted Bernheim, but am doing my best to get a bottle.
Malt Whiskey, just like rye and wheat whiskey, differs from the bourbon regulations in one way - by requiring at least 51% of the grain be malted barley. There are very few American brands of this, and the ones the do exist are, for lack of a better term, American-made Scotch. Clear Creek Distilleries in Oregon makes a malt whiskey, as does St. George Spirits in Alameda, California.
Rye Malt Whiskey must contain at least 51% malted rye grain. Anchor Steam's Old Potrero is made with 100% malted rye. As an aside, Anchor Steam's Junipero Gin is outstanding.
Corn Whiskey diverges significantly, in part, from the bourbon-type regulation template. Corn whiskey must be made with at least 80% corn grain and need not be aged in wood. In fact, if it is, the wood cannot be charred or fired. Basically, corn whiskey is an unaged spirit that resembles Prohibition-era moonshine. It's pretty nasty. Georgia Moon makes a corn whiskey. So does Platte Valley.
Tennessee Whiskey includes Jack Daniel's and George Dickel. These whiskies are filtered through maple charcoal before they are aged in barrels. This filtration, known as the Lincoln County Process, is unique to Daniel's and Dickel. There is some debate about the differences between Tennesse whiskey and bourbon, and some believe that there is no reason that these whiskies can't be legally called "bourbon." Chuck Cowdery explains this, in his usual expert manner, here.
Scotch must be distilled in Scotland. According to the Scotch Whisky Order of 1990, Scotch must be distilled from water and malted barley, to which only cereals and other whole grains can be added. The mash must be "converted into a fermentable substrate" by only endogenous enzyme systems, meaning the enzymes that play a part in the distillation must come from the grain initially added - not from independently introducing enzymes into the mash. Scotch must also be fermented solely with yeast. It's distilled to a strength of less than 94.8%, which ensures that the whiskey retains the flavors and characters of the raw materials used in its production. Further, Scotch has to be matured in Scotland in oak barrels for no less than 3 years and 1 day, and cannot contain any additives but water and/or caramel coloring. Finally, it cannot be bottled at less than 80 proof.
The most popular Scotches are the single malts. These include Glenfiddich, Glenmorangie, Macallan, Bowmore, etc., etc., etc. The taste, body, character, and color of Scotch varies greatly depending upon the region of Scotland in which it was made. My favorites come from the Islay, like Lagavulin and Laphroaig.
Canadian Whiskey like all other whiskies is produced according to specific regulations. It has to be mashed, distilled, and aged in Canada for at least 3 years. Aging occurs in wooden barrels with capacities no greater than 700 liters. Canadian whiskey is made from a mash of cereal grain or cereal grain products and the enzymes used to break down the starches of the grain need to be derived from malt "or other enzymes," and fermentation has to occur from yeast or other natural organisms. This whiskey can't be bottled at less than 80 proof, and it may contain caramel and flavoring additives.
Comparitively, Canadian whiskey has relatively lax regulations governing its production. Popular Canadian whiskies include Crown Royal, Forty Creek, and of course, Canadian Club, which was regularly smuggled over the border during Prohibition and distributed around the U.S. These whiskies are known for their subtle, light flavors and smoothness.
Irish Whiskey must be produced in Ireland or Northern Ireland to be labeled as such. Irish whiskey must be produced with cereal grains, and the starch in those grains have to be converted to sugar by enzymes contained in malt and/or other natural enzymes. Like Scotch, Irish whiskey is distilled at an alcoholic strength of less than 94.8% by volume to preserve the aroma and flavor derived from the materials used. It also has to be matured in wooden casks for at least 3 years, either entirely in Ireland, entirely in Northern Ireland, or some combination between them. Bushmills, Jameson, Redbreast, and Black Bush are some examples.
Whiskey is whiskey, right? Well, not exactly. The subtle differences in production can make marked differences in the final product. Go forth and taste.