To know the difference between whiskeys, we need to first understand what whiskey actually is. Whiskey is any alcohol distilled from fermented grain mash, or occasionally, corn (which doesn’t always have to be aged). All whiskey is distilled to a minimum of 40% alcohol by volume (ABV), up to a maximum of 94.8% AVB. The difference between the variations of whiskeys relies mostly on the type of grain used for the mash.
For a spirit to be called a Scotch, it must be made in Scotland with Scottish ingredients, including water and malted barley (other whole grains may be added). It must be aged in oak casks for a minimum of 3 years. Single malt scotch tends to have a more smoky aroma and flavor, which is caused by drying the barley grain over a pungent peat fire.
To qualify as bourbon, the spirit must be made from a grain mixture that contains at least 51% corn and made in the United States. Bourbon has no minimum aging period, but to be called Straight Bourbon, it must be aged for at least 2 years and have no colour, favouring or other spirits added. It must be aged in charred new oak barrels.
Rye Whiskey can refer to two different, but related types of whiskey:
Canadian rye whisky: There are no requirements for rye grain to be used to make Canadian rye, the label is legally permitted regardless of the content, so long as it “possess the aroma, taste and character generally attributed to Canadian Whisky”. Most Canadian whiskies contain only a fraction of rye, with the exception of a few brands. Canadian whisky must be aged in wooden barrels no larger than 700L for at least 3 years.
American rye whiskey: By law, the mash must contain a minimum of 51% rye and aged in charred, new oak barrels. To be labelled as “straight rye whiskey”, it must be aged for at least two years, and has not been blended with other spirits.