Trial 7: Evaluating the Effects of the Small Batch Wave Stave Barrel on the Flavor Development of Bourbon Whiskey
By Andrew Wiehebrink, Director of Spirit Research and Innovation
Introduction
Whiskeys with higher concentrations of barrel extractives tend to be characterized as having a more mature and developed flavor profile, especially when examining younger whiskeys. As such, producers are often eager to experiment with barrel configurations that have more flavor components available for extraction. Selecting a specific char level, adding a toast profile, or increasing the surface area on the inside of the barrel are all acceptable methods of increasing oak extractive concentrations and/or elevating extraction rates. The Wave Stave Barrel from ISC has been designed to maximize extractive concentrations and extraction rates.
Objective
The goal of this experiment is to examine the effectiveness of the Wave Stave Barrel from ISC's Small Batch Collection with regard to increasing extractive concentration and improving extraction rates.
Methods
Base Liquid
Variety: Bourbon whiskey distillate
Mash Bill: 72% corn/13% rye/15% malted barley
Entry Proof: 125 proof/62.5% ABV
Trial Execution
Entry Date: December 2014
Warehouse Location: Bardstown, KY (floor 3)
Maturation Period: 12, 24, 36 and 48 months
The Trial
New make bourbon filled into the following barrels:
Four barrels of each variation were included in the experiment.
For the purpose of this experiment, Wave Stave refers to a barrel contoured to have an increased surface area. Non-Waved is used to describe any barrel tested that has the traditional stave contour and thus is not waved.
Samples were taken from each barrel every 12 months for 48 months total and then analyzed using Gas Chromatography-Mass Spectrometry (GCMS). All compound concentrations are displayed in graphs as a percent of the average concentration across all barrels in the experiment unless otherwise specified.
Results and Discussion
The Wave Stave barrel is configured as follows:
- Traditional Medium Plus toast profile
- Char #1
- 22% increased interior surface area
Data confirms the Wave Stave barrel shows an increased extraction in a very short amount of time in barrel. Table 7.1 shows extractive concentrations in mg/L for both the Wave Stave and Char #4 barrels at 12 months of age. Char #4 barrels were used as a control barrel in this experiment. Figure 7.1 displays the results after 12 months of maturation.
The Wave Stave barrel showed significant increases in extractive concentrations over the Char #4 control barrel within the first 12 months. This trend continued throughout the course of the experiment, which lasted 48 months. Figure 7.2 and Figure 7.3 show the results at 24 and 48 months respectively.
Further Insight
Results from another experiment help isolate the surface area variable further. Four-year-old bourbon whiskey was double barreled into a Wave Stave barrel as well as a barrel that features the same heat treatment (Traditional Medium Plus toast, Char #1) without the waved surface environment. Figure 7.4 presents the 16-week results, which indicate increased concentrations for all extractives for the Wave Stave barrel compared to the control and Non-Waved barrel.
Conclusions
In this experiment, data confirms the Wave Stave barrel significantly increased the amount of oak extractives over the control in as little as 12 months. In fact, the difference in extractive concentration between the Wave Stave barrel and Base Whiskey is not only maintained, but actually grows for at least the first four years of the maturation period.
It is not surprising these results would confirm the impact of the Wave Stave barrel due to its characteristics:
- The added toast profile and lower char utilized on the Wave Stave barrel likely account for the majority of the increase in barrel extractives
- The 22% increase in surface area due to the Wave Stave barrel contour increased the overall extractive concentration.
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