While Marianne Eaves was in the midst of renovating Castle & Key Distillery outside of Versailles, KY. Several years ago, she discovered an antique bottle of Old Taylor bourbon. The distillery grounds were originally owned by Col. Edmund Haynes Taylor, Jr. (known in the whiskey world simply as E.H.). NPR notes that Taylor was a “leader in industrializing bourbon production during the early 20th century.”
Taylor died in 1923, while the distillery went through several owners before eventually falling into neglect for 40 years. The grounds turned into a tangle of foliage, while the exterior of the buildings began to disintegrate, That is until 2015, when Eaves – the first female Master Distiller of Kentucky bourbon since Prohibition – alongside her business partners Will Arvin and Wesley Murry, began introducing the distillery to the modern age of bourbon production.
Though Eaves and her business partners desired to bring the modern age of bourbon into production, that antique bottle of Old Taylor, originally released in 1917, strongly inspired Eaves to use new technology to examine the bourbon’s past.
“The most dominant flavor in that 1917 bourbon was the butterscotch note,” Eaves says. “That’s something that bourbon aficionados and the ‘dusty hunters‘ recognize about historic Old Taylor bourbon is this beautiful, rich, creamy, sweet butterscotch note — and the mouthfeel of that particular bottle was really unique for a historic whiskey.”
That precise taste was exactly what Eaves desired to incorporate into Castle & Key’s bourbon, but she didn’t quite know how to achieve such a taste. While modern bourbon brands remain thorough when it comes to notes on measurements and processers, pre-Prohibition brands, such as Old Taylor, were built primarily on oral histories.
“They were just going all on flavor. They had these processes that had been handed down for hundreds of years, so they were just doing things the way the guy before them had — just knowing it would make alcohol,” Eaves says.
Although she didn’t know Taylor’s exact process to making bourbon, Eaves had both tradition and science on her side. Susan Reigler, a bourbon historian and biologist, explains that in order for a distillate to be considered bourbon, it needs to meet the basic requirements. The spirit must be grain based, while the mash bill (mix of grains) has to be 51 percent corn. In addition, it must be aged in new, charred-oak barrels; and it must not be introduced to the barrel at higher than 125 proof.
“Because of this, certainly, the process that goes on in the still is basically the same — the chemistry is the same,” says Reigler. “And the compounds in the spirit are something that can be assessed.”
And this is exactly what Eaves did. “We decided to use a good old-fashioned ‘GC’ — gas chromatography,” she says.
Chromatography is a process of separating a mixture of chemicals, whether that be in liquid or gas form, into components by running it over the surface of another substance, typically a liquid or solid. One visual example of this is typically used in classrooms by pouring a water droplet onto an ink mark on a piece of paper. The ink will separate on the paper into distinct, colored streaks. When using Chromatography on the Old Taylor bourbon, the liquid did the same thing by separating into different chemical compounds.
“Then we looked at these chemical compounds and from there, we were able to figure out what grains he was using, [and found] a yeast strain that has a similar flavor profile,” Eaves says. “So that’s how we went about it and constructed our recipe based on it, loosely. We didn’t really want to replicate what he was making exactly, but take those flavor cues from the past, and then model our recipe around that.”
The bourbon is currently distilled and will age for a minimum of four years.