In the US, Rye whiskey is, by law, made from a mash of at least 51% malted rye. The other ingredients of the mash are usually corn and malted barley.
It is distilled to no more than 160 proof (80% abv), and aged in charred, new oak barrels. The whiskey must be put into these barrels at not more than 125 proof (62.5% abv). Rye whiskey that has been aged for at least two years in this way may be further designated as "straight", as in "straight rye whiskey".
Rye whiskey has a much more fruity or spicy flavour than its sweeter bourbon cousins.
Canadian whisky is often referred to as "rye whisky" and more commonly shortened to "rye," since historically much of the content was from malted rye. With no requirement for rye to be used to make whiskies with the legally-identical labels "Canadian Whisky", "Canadian Rye Whisky" or "Rye Whisky" in Canada, provided they "possess the aroma, taste and character generally attributed to Canadian whisky", in some cases the corn-to-rye ratio may be as high as 9:1. Most contemporary Canadian whiskies contain only a fraction of malted rye.