This spicy and dry palette whiskey got its start in America when Colonial farmers found that the barley of their ancestral homes didn’t grow well in Colonial soil, and so they turned to crops that grew very well in Eastern United States—rye and corn.
In the United States, by law rye needs to be made with a mash of at least 51% rye. The other 49% includes a combination of other grains, including corn, wheat, malted rye, and malted barley. Ryes produced from large distilleries are typically about 51% rye, 39% corn, and 10% malted barley.
Like bourbon, the rules on rye require the use of new charred-oak barrels. This allows the barrel to impart more of its own flavors of oak, caramel, and vanilla into the whiskey than you get with Scotch, which generally uses second-hand barrels.