Whiskies and bourbons are two of the most popular types of alcoholic beverages in the world. Both are made from fermented grain mash and aged in oak barrels, but there are some key distinctions between the two. Bourbon must be made from at least 51% corn, while whiskies can be made from any type of grain. Bourbons are also required to be aged in new oak barrels, whereas whiskies can be aged in used barrels. The different production methods give bourbons a sweeter flavour, while whiskies tend to be more complex.