Making Kentucky bourbon: 8 things that will surprise you

At the top of the 2 Street slope, you’ll find yourself at the western end of “Whiskey Row,” a two-block stretch of Louisville that was once-before Prohibition-the epicenter of the city’s famed whiskey industry.

After almost a century of disuse and abuse, including a three-alarm fire in 2015 that threatened to consume one of its blocks, Whiskey Row is poised for a comeback. Leading that comeback is the new Old Forester distillery.

Old Forester, owned by Brown-Forman, is the only bourbon continually owned and operated by the same family before, during, and after Prohibition. Old Forester Distilling Co. once had a home on Whiskey Row. And now that its $45-million downtown distillery is complete and open to the public, the company can once again call Whiskey Row home.

“At the turn of the century, there were 89 companies up and down these blocks,” says Campbell Brown, president of Brown-Forman. Not all of them were distilleries. Some were wholesalers or labelers or shipping companies-or other business supporting the making and selling of spirits. “This was the beginning of the bourbon industry in Kentucky,” Brown says. “We’re the only company that had offices here and has been able to reemerge on Whiskey Row.”

It’s easy to hear Brown’s pride when he speaks about his family’s long legacy of making Kentucky bourbon. And he’s excited to share that legacy with visitors to the new Old Forester distillery. “We’re going to not only be able to share the whiskey-making process here,” he says, “but we’re going to tell a story that spans five generations and that sort of mirrors the history of bourbon-making in Louisville.”

The Old Forester distillery is not your typical tourist attraction, even by the standards of distilleries. While it dives into a bit of the brand’s history-including its claim to fame as the first bourbon sold in sealed glass bottles, which it first did in 1870-the distillery is not primarily a museum, nor is it some sort of kitschy interactive “experience” packed with informational wall placards and hands-on playrooms.

It’s a working distillery and cooperage-one that will produce up to 100,000 barrels of bourbon annually-and visitors can watch almost every aspect of the whiskey-making process up close and in real time.

That process includes sniffing the fruity, banana-redolent yeast fermenting in a row of four 4,500-gallon vats. It also includes watching coopers hammer together and char the oak barrels that will be used for aging the bourbon, and traversing the catwalk in a 900-barrel-capacity on-site maturation warehouse.

“We’re pumping stuff up and down this building,” Brown jokes. “We’re fermenting here, we’re using barrels that we’re making here, we’re filling those with distillate here, putting it in a warehouse here-so I’m really curious and excited to see this facility and this process will influence the flavor of the whiskey we end up with four years from now.”

You can learn a lot more about Old Forester and how bourbon is made by heading down to Louisville. But to whet your appetite, here are 8 surprising things you didn’t know about Kentucky bourbon.

Bourbon Bylaws

If you’ve ever wondered what makes bourbon different from all the other types of whiskey-from Scotch and Irish whiskey to Jack Daniel’s-understand that there are federal rulesregulating the definition of bourbon.

What are those rules? For one thing, bourbon has to be made in America. Its “mash bill”-the mixture of different grains that will be cooked and fermented and used as the foundation of the spirit-must contain at least 51% corn. The distilled liquid must be aged in new, charred-oak containers, and the finished product must be at least 80 proof (or 40% alcohol).

There are a few other stipulations-included the minimum or maximum proofs at which bourbon must be barreled and bottled.

Drink Your Medicine

If you read the top of this story carefully, you learned that Old Forester is the only bourbon continually owned and operated by the same family before, during, and after Prohibition. How did the brand stay in business during Prohibition? No, they didn’t flout the law. The U.S. Government issues six special operation licenses for the making of “medicinal whiskey,” and Old Forester was granted one of them. Back then, whiskey was considered an effective remedy for everything from the common cold to pain. Even today, some experts say a “hot toddy” could knock out some cold symptoms.

Whiskey Comes From Beer

After the mash-bill grains are mixed with yeast and water, they’re heated in order to encourage fermentation. The resulting liquid-once strained-is sometimes called “the wash” or the “distiller’s beer.”

It’s called “beer” because that’s pretty much what it is. The only difference between this stuff and Miller Light is that “distiller’s beer” doesn’t contain hops or other popular beer-flavoring ingredients, and it’s usually made with different grains and yeasts than would be used for brewing beer.

You could even drink the distiller’s beer. While not very tasty, it clocks in at a reasonable 7% to 10% ABV.

Distilling Turns "Beer" Into Gas

During the whiskey-making process, distiller’s beer is pumped into a still where it’s heated so that alcohol vapor separates from the grains and water left over after fermentation. While those left-over components sink to the bottom of the still, the vapor rises to the top. It’s captured there and converted back into liquid form by a condenser.

There are variations on this process-some using more than one still. But they all involve turning liquid into alcohol vapor and then back into liquid again.

"Sour Mash," Defined

You’ve no doubt read or heard the term “sour mash” whiskey a thousand times. But what does that mean? After the process of fermentation is finished and the resulting “wash” or “distiller’s beer” is moved on to the still, some of the yeasty, fermented mash is held back and added to the next batch of mash. This older, “sour” mash helps impart flavor and complexity to the finished whiskey.

Understanding ‘Straight’ Bourbon Whiskey

Another phrase you know well but have probably never considered: “Kentucky straight bourbon whiskey.” What does the “straight” mean in this context? According to federal regulations, to be called a “straight” bourbon, the alcohol must be aged for at least two years in new oak barrels. Also, it cannot contain any added colors, flavors, or other spirits.

Why Copper Stills Are Vital

The centerpiece (literally) of the new Old Forester Distillery is a 44-foot tall copper column still. While a lot of distillers have flashy copper-plated stills to dazzle visitors, it’s the copper on the inside that matters. This metal is naturally antibacterial and porous, and so it helps pull imperfections-most notably sulfur compounds-out of the distilled alcohol.

Kentucky Bourbon Barrels Outnumber Citizens

A lot more. So says Jackie Zykan, master taster at Old Forester. A recent report from the Kentucky Distillers’ Association backs Zykan up on that. It found that while “the Bluegrass state” is home to 4.4 million people, it houses more than 6.7 million bourbon barrels. But while dozens of producers are making bourbon in Kentucky, “Brown-Forman is the only spirits company that makes its own bourbon barrels,” Zykan says.