In April 2014 Jim Beam filled its 13 millionth barrel of bourbon at its distillery in Clermont, Kentucky. The company - the world's best-selling bourbon maker - has records going back to 1795 when Jacob Beam was the first family member to sell a barrel of the corn whiskey they had been making for several years. The name Jim Beam was only adopted in 1933 in honor of the man who rebuilt the family business after Prohibition. The current Master Distiller, Fred Noe, is the 7th generation of the Beam family to be directly involved in the company.
To take the Kentucky Bourbon Trail is to make a journey through the USA's history, through immigration, revolution and Prohibition to the modern global business world. The Beams were originally called Boehm and arrived in America from Germany in 1740, setting up as farmers. Corn production was so good here that they had an excess of it, which they turned into the corn whiskey that Jacob Beam eventually had the bright idea of selling.
Today bourbon - 95% of which is made in Kentucky - is big business, and business is booming. Companies like Jim Beam can't fill barrels fast enough.
Thirty miles away, in Loretto, is another famous bourbon maker which grew out of immigrant stock: Maker's Mark. In this case the ancestors came from Scotland, which is why they chose to use the Scottish spelling of 'whisky' rather than the American 'whiskey'.
Maker's Mark was first bottled in 1958, though the Samuels family which founded the company had been distilling in Scotland back in the 1500s. Today Maker's Mark is distinguished by the red wax seal around the top of the bottle, and part of the visitor experience here is to try your hand at dipping the bottle into the molten wax - with varying degrees of success. In my case I was told I could have a job there any time, which was tempting as the Maker's Mark distillery is set in rolling green Kentucky hills. A sunny April day is deceptive, though, as the Kentucky climate is another of the factors that makes bourbon bourbon.
'We have harsh winters and hot summers, which accelerates the ageing process,' says Rob Samuels, the 3rd generation of the Samuels family making Maker's Mark. 'A 5-year-old bourbon is equivalent to an 18- to 20-year-old Scotch. It's no accident that bourbon is made in Kentucky. Bourbon can be made anywhere. One reason it's here is the limestone shelf which produces a natural source of iron-free water. We have a 14-acre spring-fed lake. We believe we're the only distillery in the USA that takes all its water from its own spring.'
We drive east to Lawrenceburg, to Wild Turkey. It's an idyllic agricultural landscape of gentle, lush hills and thick woods, where herons stand by fast-flowing rivers and eagles soar in the deep-blue skies. And as we approach the distillery, which stands 300' above the Kentucky River on Wild Turkey Hill, I do indeed spot a small flock of wild turkeys in a tree at the side of the road.
It's a pleasing sight as for me the pleasure of the Kentucky Bourbon Trail is not just the chance to sample and discover new bourbons, but to enjoy the rural scenery and take in this particular part of American history. The founding of Wild Turkey dates back to 1869, and the present Master Distiller, Jimmy Russell, has been with the company for 60 years. It was Jimmy Russell who, twenty years ago, came up with a product that has been one of the bourbon industry's biggest recent successes: a bourbon honey liqueur.
'He first made it for his wife,' says our tour guide, John. 'She didn't like regular whiskey but he wanted her to like something he made. It's now the 2nd-best seller of all our products.'
Just 13 miles from Wild Turkey is another name that will have bourbon lovers reaching for their shot glasses: Woodford Reserve. Whiskey has been made on this site since 1780, though that distillery was closed several times, burnt down, rebuilt, closed again during Prohibition and the land sold to a farmer. In 1992 it was bought back again and the distillery restored, with the first production of Woodford Reserve (named for Woodford County where they're located) in 1996. They sold 125 cases.
Last year Woodford Reserve sold 250,000 cases, making it the best-selling premium bourbon in the USA. With 130,000 visitors in 2013, it's also the most popular distillery in Kentucky. With its small scale and pretty setting, and the prestigious name of Woodford Reserve, that's hardly surprising.
It's at Woodford I discover that alongside the history there's still the thrill of modern discoveries too. As we taste after our tour we're given a glass of Woodford Reserve Double Oaked, which was first brought out in 2012. To make it they take Woodford Reserve - already a premium bourbon - and put it into a second new barrel. The barrel, though, has been specially made to the distiller's instructions. It's toasted for four times longer than the average barrel. Toasting is a process like toasting bread, which intensifies the flavours of the wood. Each barrel is then charred - set alight for five seconds then doused in water.
The result of the distiller's devilish skills, combined with the barrel-maker's expertise, is a sweeter bourbon, a dessert bourbon, with intense tastes of butterscotch, honey, caramel, butter, vanilla and crème brulée. It's the finest bourbon I taste, and shows that the industry is alive and well along the Kentucky Bourbon Trail.
Mike Gerrard is an award-winning writer who specialises in writing about travel and drinks. He has previously written about Cognac and Jarnac for The Huffington Post, and is co-editor of the 101 USA Holidays website
Visiting the Kentucky Bourbon Trail
You can make your own tour along the Kentucky Bourbon Trail by renting a motorhome throughFrontier Motorhomes, which should give you plenty of room to store any purchases.