"People keep asking us, 'When will the bubble burst?'" said Eric Gregory, president of the Kentucky Distillers' Association.
For most in the business, the answer is not anytime soon.
Large companies are banking on continued international demand from places such as China and a culture in the U.S. that currently has a taste for bourbon, which has to be aged at least two years in new charred oak barrels.
"We are busier than I ever could have imagined," said Chris Morris, master distiller at Brown-Forman Corp., producer of Woodford Reserve and Old Forester bourbons.
Last year, Kentucky distilleries filled 1.2 million barrels of bourbon — the most since 1970, according to the Kentucky Distillers' Association. Inventory has topped 5 million barrels for the first time since 1977, the group said.
Production has surged by more than 150 percent in the past 15 years in Kentucky — home to 95 percent of the world's bourbon production.
"For many, many years, bourbon was considered a Southern gentleman's drink," said Jimmy Russell, the longtime master distiller at Wild Turkey. "Now bourbon's become a worldwide drink."
The last time the industry spiked production in the 1970s, distillers ended up with a glut when demand went in a tailspin.
Back then, the industry had grown stale and many consumers switched allegiance to vodka, Scotch and other spirits.
"You had the same old brands, you were pretty much on autopilot," Morris said.
Now, distillers are constantly dabbling with premium small-batch offerings or putting new twists on recipes and flavors and companies are looking to real-time data from the digital world.
Sales trends and developments are tracked in markets worldwide. The numbers are crunched to make the best educated estimate of future consumer demand for a product that takes years to mature.
Straight bourbon whiskey ages a minimum of two years, though the average maturity is four years or older. Many popular super-premium brands age six years or longer, which are the toughest to stock in bars, restaurants and liquor stores.
"Bourbon as a category is on fire," said Bill Thomas, a Washington, D.C., bar owner whose establishments include Jack Rose Dining Saloon. "Every week, there's stuff that's out of stock."
Expansions have occurred at Jim Beam, Evan Williams, Wild Turkey, Maker's Mark, Buffalo Trace and Woodford Reserve. Global liquor giant Diageo PLC recently announced plans to build a new distillery in Kentucky. Microdistilleries are getting a foothold in the state.