First things first, it's important to note that the big spirit companies have spent a lot on marketing over the past 10 years in an attempt to take marketshare from the beer categories (their number one market competitor). Here's Diageo, for example:
Thanks to Google Trends we're able to see the direct impact of that marketing since 2004 and quantify the interest in bourbon as measured by the relative number of Google searches. What this plot shows is that search interest is steadily increasing as more and more people are getting familiar with bourbon.
When we plot the normalized google searches alongside the normalized mean of each auction, what's clear is the interest in bourbon and the price of bourbon have finally converged. More people have gotten into bourbon and the cost to aquire the brown stuff has finally started to reflect the new, higher priced reality. Given the discrepency between price and searches during 2009-2013, one could say that with respect to interest, bourbon was a mispriced asset.