Although all whiskey is produced using fermented grain, different types use different base products and differ in quality and alcoholic content. There are three primary types of whiskey. Malt whiskey is produced from malted barley. Grain whiskey is produced from any fermented grain. Finally, some whiskey is a combination of malt and grain.

One of the important things to remember about all types of whiskey is that the product never ages in the bottle, only in the cask. The cask is of the utmost importance in whiskey production. Chemically, the whiskey is changed by the oak cask. Thus, the age of whiskey is defined as the time between distillation and bottling.

Whiskey that has been in the bottle for many years is rare but, since aging does not continue in the bottle, an older bottle of whiskey that was aged the same as a newer bottle is of no better quality. Additionally, ten years is the maximum aging time that makes a difference for whiskey. Any time spent in the barrel beyond a decade makes little difference in the taste of the whiskey.

Malts and grains can be distilled individually or combined to make a variety of whiskey types that fall into several groups:

Single Malt Whiskey malt whiskey produced from the whiskey of a single distiller. It is important to remember that unless the whiskey is labeled “single-cask”, it is most likely whiskeys from multiple casks blended to get the taste associated with that distiller’s product.

Vatted Malt Whiskey malt whiskey produced from a blend of whiskeys from multiple distilleries. Typically, when a whiskey is labeled as “malt” or “pure malt”, the consumer can assume that he or she is purchasing a vatted malt whiskey.

Blended Whiskey whiskey produced by mixing both malt and grain whiskies. In addition to both malt and grain whiskies, blended whiskey typically includes caramel, natural spirits and flavoring that are also blended to create the final whiskey product.

Single Barrel Whiskey specialty whiskey in which every bottle is from a unique cask. Each bottle of single barrel whiskey can have a distinct flavor. Often the individual bottles are labeled with the specific cask number.

Cask Strength whiskey that is bottled from the cask without dilution. This type of whiskey is also known as barrel proof. Cask strength whiskey is exceedingly rare in the present day and only found when dealing with highest quality product.

Distillation is an ancient art that began as early as the second century in Mesopotamia. Before distillation was used to create alcoholic beverages, it was used to create perfumes. The knowledge of processes related to distillation spread quickly through Europe. Distillation for the purpose of creating alcoholic beverages first spread through European monasteries that used alcohol as medicinal treatments.

Around 1100, distillation spread to Ireland and monastic distilleries soon followed. Up to this point, portable alcohol had primarily been created from distilling grapes into wines. However, grapes were uncommon in Ireland, and distillers soon found that they could substitute barley grain to create a very drinkable alcohol. This was the birth of the drink we know as whiskey.

Until the mid-1500s, whiskey production remained primarily in the hands of monks. However, King Henry VII dissolved the monasteries between 1536 and 1541. At this point, Irish monks assimilated into the larger society and took their whiskey making knowledge with them.

In these early years of whiskey making, the drink was consumed shortly after distillation and was very raw when compared to whiskey as we now know it. Over time, distillers discovered that aging the raw distilled barley grain resulted in a smoother, far more drinkable product. With this discovery, modern whiskey making was born.

The popularity of whiskey only increased as time passed. During the American Revolution, whiskey was used as currency. Used for both trading and consumption purposes, whiskey, primarily imported from Ireland, was highly coveted in the American states. In 1794, the Whiskey Rebellion resulted when an additional excise tax was levied on whiskey.

In the early years of the United States, many Irish immigrants brought their whiskey making knowledge to their new home. American whiskey became increasingly popular through the 1800s. Several factors led to the increasing popularity of whiskey throughout the nineteenth and twentieth centuries. First, in 1826, the continuous still was invented by Robert Stein. In 1831, the continuous still underwent further innovation when Aeneas Coffey created the Coffey Still. These innovations made it easier and less expensive to distill whiskey. Not long after the Coffey Still was introduced, Andrew Usher first introduced blended whiskies in 1850. These blended whiskies mixed traditional pot still whiskey with whiskey produced using the Coffey Still. Blended whiskey was primarily embraced by American whiskey makers. For the most part, Irish whiskey makers rejected both the Coffey Still and blended whiskey products, clinging to traditional whiskey making procedures. Thus, the introduction of the Coffey Still resulted in a major deviation between Irish and American whiskey products from the mid-1800s onward.

Some types of whiskey that have strong United States federal regulations include:  

Malt Whiskey, Rye Whiskey, Rye Malt Whiskey, Wheat Whiskey, Bourbon Whiskey, Corn Whiskey.

According to United States regulations, the mash for each type of whiskey must be at least 51% pure grain. Additionally, each of these types must be distilled in such a way that they do not contain more than eighty percent alcohol. Also, it is important to remember that the addition of coloring, flavoring and caramel are not allowed in the production of American whiskey.