Mash Bill
A mash bill is the mix of grains used to make a spirit. Theses grains are cooked and fermented to begin the whiskey making process. Common grains in a whiskey mash bill: Corn, Rye, Wheat, and Malted Barley.
Age or Age Statement
An age statement is typically the minimum amount of time a whiskey is aged in a barrel. If its a blend of whiskies, the age statement would show the shortest amount of time aged in a barrel. For example, an 8 year and a 12 year blended whiskey would be labeled as an 8 year whiskey. Some times you may see NAS, which means No Age Statements
Proof
Proof is the measurement of whiskey, which is twice the percentage of alcohol by volume. For example, a 90 proof bourbon is made up of 45% alcohol by volume. The higher the proof, the more ethenol burn you will get from the spirit.
Straight Bourbon
Straight Bourbon is a type of bourbon that is traditionally made with at least 51% corn and aged for a minimum of 2 years.
High Rye
A whiskey that has more than 51% rye is considered a high rye. High Rye is typically made with a 70% rye mash bill.
Bottled in Bond
A whiskey that is bottled in bond is created and aged in accordance to a set of regulation that is goverened by the United States Bottled-in-Bond Act of 1897. The liquor must be the product of one distillation season (January–June or July–December) by one distiller at one distillery. It must have been aged in a federally bonded warehouse under U.S. government supervision for at least four years and bottled at 100 proof.
Sour Mash
A process used in the distilling whiskey that uses material from an older batch of mash to start the fermentation of a new batch, analogous to the making of sourdough bread with a starter.
Cask Strength or Barrel Proof
Cask strength whiskey is simply distilled and aged whiskey bottled directly from the cask at the distillery. This means that it hasn't been diluted, so it has a much higher ABV.