Canadian whisky is a complex and somewhat confusing whisky style. Officially, to be labeled Canadian whisky the spirit must be distilled from a mash of cereal grains and aged for a minimum of three years. Most examples are blends, and they almost always include some percent of rye whisky, though not always.
It is a common misconception that Canadian whisky is rye whisky, and the two terms are often used interchangeably. This stems from the time when rye was added to spirits, mostly based on wheat, to improve their flavor. The name rye whisky soon caught up, and it was often used for most Canadian whisky styles—regardless of their rye content.
Corn is probably the most important grain, but rye provides the most flavor. All these elements influence the great diversity among the category. Canadian whisky rose in popularity during Prohibition. It was smuggled and supplied to speakeasies that were scattered across the States.
Even after the Prohibition, it was the whisky of choice among Americans, mostly because of its lighter character. Nowadays, some of the best-selling whiskies in the United States are Canadian. For a very long period, Canadian whisky got a bad rep because of their blending technique.