Bourbon, also referred to as “straight” bourbon, is a grain whiskey made from at least 51% corn, using new-charred oak barrels, and aged for a minimum of two years. If aged less than four years, it must include an age statement.

Its’ name comes from Bourbon County, a formerly larger geographic area covering Kentucky and Virginia. The type of whiskey from this area was called “Bourbon” to distinguish it from the primarily rye whiskey from Pennsylvania. Curiously, there are no distilleries in the current (and much smaller) Bourbon County in Kentucky.

The ingredients for bourbon are water, corn, yeast, and two other grains: one being barley which helps in fermentation and adds character, the other usually being rye, but in some cases, wheat. If the latter is used, it is referred to as a “wheated” bourbon.

Sourmash refers to fermented grain and yeast solution that is used as a “starter” from a previous batch (much like sourdough bread), which creates the next batch of bourbon. Sourmash is also known as “setback.” Many distilleries use the sour mash process as it is thought to  guarantee a more consistent product not that it affects the distilling or taste of the finished product to a great extent.

While most bourbon is produced in Kentucky, the only legal geographic requirement is that it is produced within the United States. Indeed, there are may new microdistilleries all over the United States that produce bourbon including a more or less local one, Honeoye Falls  Distilling. Other requirements are that the whiskey is not distilled over 160 proof, is barreled for aging at no more than 125 proof, and is bottled it no less than 80 proof. No coloring or flavoring agents are allowed to be added to the whiskey.

Bourbon is  the only whiskey that gains proof while it ages- all other whiskeys and many other types of spirits tend to  lose it during the aging process . This is due to the temperature extremes and general conditions it is stored in.