Extraction of Wood Constituents from Non-Conventional, Small Whiskey Barrels

In the aging of whiskey spirits, oak barrels provide vessels for containment which are semi-permeable to the spirit and to outside air. The barrel wood itself provides extractives derived from structural polymers which have been degraded during barrel construction. These extractives have a large cumulative effect on the sensory characteristics of the aging spirit. The traditional barrel for the aging of spirits ranges from 52-60 American gallons and has been employed in the same basic size and form for centuries. Recent growth in themerican craft distilled spirits industry has increased the use of reduced volume barrels ranging from 2-30 American gallons. These smaller barrels provide more rapid extraction and to some extent more rapid oxidation and maturation. While a good deal of research has addressed the topics of extractive concentrations and reactions in the traditional industry, very little information is available on reduced volume barrels. The current study by tracks rates of extraction from 2,3,5 and 10 gallon barrels over the course of 200 days. Four phenolic compounds were chosen for monitoring by gas chromatography coupled with mass spectrometry detection (GC/MS). The results indicate very high rates of extraction to the higher surface area to volume ratios of the smaller, non-conventional barrels.