http://insiderlouisville.com/news/2013/12/29/costcos-private-label-bourbon-wait-say-costco/
Or not…
Mitch Huffington • a day ago −
I believe you are wrong on your conclusion of Buffalo Trace as the source of Kirkland Bourbon. Clermont is the home of Jim Beam. They also list Frankfort for Jim Beam owns the Old Grand Dad distillery just down the road from Buffalo Trace. I also had a chance to taste it when Costco hosted a tasting. The distributor was the one running the tasting and in conversation even said it was a Jim Beam product. That being said it is a middle of the road bourbon and would drink it again. Comparable to a Knob Creek.
Clermont is also the home of Knob Creek.
All rumours I have heard/read is that the Kirkland is a young Knob Creek. Whether it is that or something else, it doesn’t matter - I will be keeping a bottle around for mixing and cooking.