By: Scott Ritenbaugh
Even though bourbon can be made anywhere in the United States, over 95% of it is made in Kentucky. Bourbon’s birth and heritage reside in Kentucky, but you may be asking yourself why.
There are five main reasons why Kentucky is where bourbon began and how it became the product we know.
Many people talk about the importance of the limestone water of Kentucky and its
importance in bourbon making. Some people even think that the limestone water is part of
the legal definition of bourbon. Even though it’s not a prerequisite to making a bourbon,
Kentucky’s limestone water plays an important role. Kentucky sits on a bed of limestone and when ground water filters through it two things happen. The first is that the limestone adds nutrients like magnesium and calcium to the water that help the yeast thrive during the fermentation process. Second, it removes iron from the water, which is very important. If bourbon is made with water that has a high iron content it will turn black during the aging process.
Bourbon wouldn’t be what it is without a barrel and the barrel wouldn’t impart the range of flavors we know and love into the spirit if it wasn’t made of oak. Oak is the most prevalent species of tree in Kentucky. The availability of this abundant wood led coopers to make barrels out of what ended up being one of the most important parts of bourbon’s flavor profile. Oak is the most appropriate wood for barrels, because when milled correctly, it is liquid tight.
Kentucky’s soil is fantastic for growing crops, and in particular, corn. It was when the settlers of Kentucky found themselves with excess corn that they decided to ferment and distill it, rather than try and transport it or let is spoil. It’s this heritage that eventually led to the regulation that bourbon’s mash bill must contain at least 51% corn.
When early settlers were distilling, they couldn’t just order distillers yeast; there was no such thing at the time. Luckily for them, Kentucky has abundant wild yeast that would attach itself to cooked mash and start the fermentation process. The process of letting environmental yeast find its way into your
mash to start the fermentation process, as opposed to adding yeast to the fermenter, is called wild fermentation. And it was Kentucky’s plentiful yeast and its ability to attach to fermentation that made distilling and bourbon production so successful in the state.
Kentucky has both hot, humid summers and cold dry winters, which are important factors in the aging process. This yearly swing in temperature causes the bourbon to be pushed in and pulled out of the oak that the barrel is made from. It is this push and pull process the bourbon goes through during
aging that helps impart the oak characteristics. If bourbon was aged in a climate that was temperate year round, the bourbon would take much, much longer to get the oak characteristics out of the wood, and not as many characteristics would be transferred.