U.S law states that rye whiskey must contain at least 51% rye grain in the mash tun (similarly, Bourbon must contain at least 51% corn), lending the spirit a distinctive spicy flavour. By contrast, corn whiskey must contain an absolute minimum of 80% corn grain in the mash tun, and are a throwback to the very first whiskeys produced in America. Canadian-produced rye whiskies are not subject to the same strict regulation, but nevertheless tend to be characterised by the spicy rye influence.