Bourbon whiskey is having a moment. To find out why the preferred drink of Kentucky is taking on the world, we take a journey along the Bourbon Trail.

“Actually, that one’s not quite right.” There are about 40 fluted glasses lined up in front of us, each one approximately half-full of the crystal-clear spirit known in the liquor business as “white dog.” Denny Potter, the composed, crookedly handsome fellow who happens to hold the position of master distiller at Maker’s Mark, has been working his way down that line, performing just one of the company’s many quality-control steps. One at a time, he raises the glass to his nose, takes a deep sniff while leaving his mouth open to increase circulation, then places it back in line. The first 18 glasses have passed muster, but there’s one that has him concerned.

“Give me a minute to mark it down,” he says. “I know what the problem is.” Each batch of white dog must pass Potter’s nose before being placed in a brand-new white oak barrel, complete with carefully charred interior, for between four and seven years. At the end of this process, it will become Kentucky bourbon. For the glass in Potter’s hand, however, and the entire batch of distilled liquor which it represents, the story will end here. “Distilling is both biology and chemistry,” the man explains. “It’s biology in the early stages, where you ferment your mash, then it becomes chemistry during the distillation process and afterwards.”

The offending batch has failed for biological reasons; there was something not quite right in the “mash bill” of corn, malted barley, and winter wheat that produced it. A sophisticated gas-chromatograph machine will evaluate the chemical composition of the white dog and determine exactly what has happened. Why not use this modern technology to test all the batches? “The nose,” Potter replies, “can often detect more than the machine.”

Perhaps that explains why the 13 distilleries on Kentucky’s “Bourbon Trail” are experiencing a period of absolutely unprecedented success. American whiskey is the third best-selling type of alcoholic spirit in the United States, trailing only vodka and rum, and Kentucky bourbon makes up a big part of that success.

What’s the difference between whiskey and bourbon? It’s simple. At least 51 percent of the “mash bill” must be corn. It must be stored in new, charred white oak barrels for at least a year. It must be at least 60 proof, and the water used to dilute it must be limestone-filtered. In 1964, Congress passed a law stating that the name “bourbon” can only be applied to whiskey produced in the United States using the above rules. About five percent of American bourbon is made by small distilleries everywhere from Chicago to the Finger Lakes region of New York—but the vast majority of it comes from Kentucky.

You might say that bourbon flows in the Bluegrass State’s veins. It employs thousands of people along the long stretch from Bardstown to Lexington, figures prominently in family histories of the area, draws seemingly innumerable tourists from all around the world. You cannot write the history of Kentucky without writing a history of bourbon along the way.

We’ve brought the new Mazda CX-5 Signature to the Bourbon Trail for a carefully curated tour of three distilleries. Our first stop is Maker’s Mark, widely considered to be both the originator of premium bourbon and its most prolific manufacturer. During our tour, Denny Potter shows us swimming-pool-sized wooden barrels of mash, intricate copper fermenters that have the appearance of Victorian-era machinery because, well, they are Victorian-era machinery, and the massive column stills that produce the final product.

The life cycle of Kentucky bourbon is simple enough in the abstract. The grain that makes up the mash blend is ground to a fine powder, mixed with water, then cooked. Afterwards it is cooled before being put in a fermenting barrel along with a fresh batch of yeast. Most of the barrels contain a system of cooling tubes to reduce the heat of fermentation. When you drain the barrels, you have “beer” containing about nine percent alcohol by volume.

That beer is heated in the still and the resulting vapor is collected as “white dog,” about 60 percent alcohol by volume. In most cases, several batches of white dog are mixed together before being put in the barrel, to ensure consistency of taste; the resulting product is “blended” bourbon. “Single barrel” bourbon, on the other hand, is the product of a single distillation process.

Maker’s Mark started with a single recipe but now offers a variety of bourbons to accommodate the increasingly diverse and demanding tastes of today’s connoisseurs. Their “Private Select” program offers customers a chance to create a personal barrel of a strength and flavor most closely matching their tastes; less ambitious buyers are offered a chance to dip a newly purchased bottle in the company’s trademark red-wax seal.

The success of these programs, along with a serious uptick in bourbon sales, has led to a rapid expansion in the number of buildings surrounding the original distillery. A brand-new experience center features a million-dollar glass ceiling by American artist Dale Chihuly and a host of private suites for lengthy and detailed tasting parties.

“Maker’s Mark’s “Private Select” program allows customers to create a barrel of a strength and flavor most closely matching their tastes”

Alas, there will be no tasting on the schedule for me or photographer Matthew Allen. After purchasing a bottle of single-barrel bourbon for future enjoyment, we fire up the CX-5 for a backroads jaunt in which we are both sober as church mice but thrilled nonetheless. The narrow two-lane out of Loretto, Kentucky, is alternately reminiscent of Watkins Glen and Laguna Seca, bordered on both sides by low foliage and broad fields from which stout horses gaze unconcernedly at our considerable pace.

During the Prohibition Era, many of these roads ran into the mountains and terminated in secretive, illegal distilling operations. It was not uncommon for a whole family, or a whole town, to be in on the secret. Once the Eighteenth Amendment was repealed by the Twenty-first, however, several firms rushed in to start mass production of Kentucky bourbon once again, including our next destination, the Stitzel-Weller Distillery. Opened on Derby Day in 1935, closed in 1992, and now operated by Bulleit Frontier Whiskey, the facility now serves as a cultural touchstone for Kentucky bourbon in general and Bulleit in particular.

Largely a museum where tourists can poke through an original barrel-repair shop and marvel at the continued integrity of the black-dyed post-Prohibition facilities, Stitzel-Weller also maintains a small test facility where head distiller Andrew Yourick develops new processes and recipes to expand the Bulleit lineup. “Nowadays, we all have to be scientists,” Yourick notes; his degree is in the recherché but profitable field of fermentation science. “Every distillery is different—the equipment, the processes—and that’s why nobody even tries to duplicate anybody else’s product,” he explains. Visitors who want a taste of the old days can try Blade and Bow, which mixes recently distilled spirits with the last of the 1992-era bourbon.

“EVERY DISTILLER IS DIFFERENT—THE EQUIPMENT, THE PROCESS—AND THAT’S WHY NOBODY EVEN TRIES TO DUPLICATE ANYBODY ELSE’S PRODUCT”

Our final destination for the day, located nearly an hour south, is Limestone Branch Distillery. You won’t recognize the name of the place, but you might recognize the name of its owners: Steve and Paul Beam are seventh-generation distillers whose family name echoes across Kentucky on bottles, corporate statements, and rusty old mailboxes.

In 2010, they founded Limestone Branch; four years later, they acquired the Yellowstone brand that had adorned whiskey made by their ancestors from 1872 to 1944. “We are making about a barrel’s worth a day,” Steve Beam laughs, “but we are heading towards making two.” After watching the Maker’s Mark facility fill one new barrel every three minutes or so, it is fascinating to see Limestone’s single steel 55-gallon drum fill up at a pace roughly equivalent to what a child could sip through a straw. Everything about the place is, quite literally, small batch­—right down to the 15-gallon barrels stored in a container unit outside the main building. “We touch everything,” Beam notes. “No computers, no automation. It’s hands-on.”

“EVERYTHING ABOUT THE PLACE IS, QUITE LITERALLY, SMALL BATCH­—RIGHT DOWN TO THE 15-GALLON BARRELS STORED IN A CONTAINER UNIT OUTSIDE THE MAIN BUILDING”

I ask Beam why bourbon has become so popular in recent years. “It is all of Kentucky, distilled into a single glass. It’s a craft. It’s an art form. And it’s done best in Kentucky. The limestone water, the grain, the climate—all perfectly suited to bourbon.” In addition to the primary Yellowstone brand, the Limestone distillery sells individual bottles with specific dates, mixtures, and proof numbers. It is possible to meet, and speak with, the man who made that bottle; the entire distilling staff, including Beam, would fit comfortably in our five-passenger SUV.

Given world enough and time, we could visit all 13 distilleries on the Bourbon Trail. Some tourists make a whole week out of it, while others are content to take one of the many single-day bus tours which allow them to imbibe along the way. Regardless of how you choose to take the Trail, however, you’re certain to be charmed by the diversity, variety, and historic nature of the places you will visit. And that warm feeling you get in your throat after drinking the stoutest bourbon blends? Well, the old-timers like to say, that it’s just Kentucky wrapping its arms around your heart.

THE MAZDA CX-5 Signature

Prohibition-era Kentucky bootleggers were known for driving some genuine hotrods, but they would have leapt at the chance to wheel something like the new CX-5 Signature. The turbocharged 250-horsepower Skyactiv-G and standard all-wheel-drive would have left federal “revenuers” of the era in the dust; the spacious cargo compartment would have carried a few barrels with room to spare.

Would they have appreciated the ventilated-and-heated Nappa leather seats in Caturra Brown, the layered-wood trim, or the full suite of electronic driver aids including Mazda Radar Cruise Control with Stop-and-Go? It’s very possible; these are the kind of luxuries that seem a bit extravagant on a test drive but quickly become almost indispensable. As the flagship of the popular CX-5 line, the Signature adds both power and polish to what was already the sports car of compact crossovers. The result is compelling, indeed.