A bourbon barrel manufacturer has been having a problem with staves breaking when barrels are assembled. The company was breaking an average of 6 staves per barrel - in other words, they were breaking or having to rework about 18% of their production. Based on information from an out-of-state consultant, the company has been under the impression that the staves break because they are being dried too quickly or at too high a temperature. 

Chad Niman and I (Extension personnel from the UK Department of Forestry and Natural Resources) arranged to visit with the company about this problem. In advance of our visit, I requested samples of defective/broken staves to examine.

The staves came from barrels that had been "hooped up", and they all showed breakage across the grain. This is an unusual form of breakage; it constitutes brash failure, whereas bending failures in wood normally exhibit splintering tension failures.My visual examination indicated that the breakage was caused by the presence of incipient decay.

It was apparent that the staves had been stored in a moist environment and that they must in fact be in close with the ground, at too high a relative humidity. These conditions  promote the growth of decay organisms.

Incipient decay not only can cause brash wood failures, but the presence of fungal hyphae in wood will increase the wood permeability. This can be important for the bourbon industry, because losses of bourbon during maturation add up to significant losses. I recently had a conversation with one of this company's customers about this issue, as they were wondering if there was some way to reduce the loss of alcohol during storage in "rick houses". They represented to me that the losses were in the range of millions of dollars per year. When we spoke, we were all unaware of any problems with the staves at the stave manufacturer.

I confirmed the presence of incipient decay through microscopic examination.

I prepared photographs showing the presence of hyphae and spores in the wood, and I wrote a comprehensive report with recommendations to demonstrate how to remedy the problem. Among other things, I recommended that the staves be raised off the ground to reduce the humidity and eliminate the potential for decay. 

After presenting the report and discussing it with the plant manager, he indicated that he would implement my recommendations. He further noted that his company would save a minimum of $4 million per year, and very likely as much as $9 million dollars for every year after the changes were made. 

After the meeting, Chad Niman and I looked at the stave storage and drying area. It was obvious that the staves were in an area that would receive runoff rain water and that there was a lot of vegetation surrounding the staves; they were also set very close to the ground, and some were even in standing water. 

I made a second report for the plant manager noting my findings, including recommendations to regrade the property to remove standing water. I recommended considering buying additional property to spread out the ties and promote air flow. I also included photographs of air-drying yards from different sorts of wood-using industries to give the company a visual album to aid them in re-configuring their air-drying operations.

My recommendations will assist this company to completely eliminate decay from their drying and storage area. This company will be able to completely eliminate the breakage and rework of defective staves. They will also be able to make barrels that lose less bourbon during storage. Depending on the number of barrels stored in distillers'' rick houses for maturation, this will likely save their customers millions more dollars per year per distillery by reducing their alcohol losses during maturation. My analyses, site visit and reports will save both the stave manufacturer and their customers many millions of dollars during each year that they are in operation.