Corn whiskey, as its name suggests, is made primarily from corn. So is bourbon. But unlike bourbon or other brown whiskies, like Jack Daniels, or rye or Scotch, it spends no time aging in wood barrels. It's the wood-aging that adds color to distilled spirits. And, with no aging needed, it can be produced relatively quickly - it can be produced and bottled in a few weeks. Brown spirits typically spend years in barrels before bottling.
Today, clear and unaged corn whiskies are among the hottest trends in the spirits industry today. National brands include Shine On Georgia Moon and Junior Johnson's Midnight Moon.