Independent Stave. The creation of the charred bourbon barrel.

Independent Stave Company (ISC). I did things a bit backwards in the world of casks and barrels. I visited Speyside Cooperage, in Scotland first. Here they don’t assemble new barrels, but re-assemble the broken down staves from ex-bourbon and sherry barrels. Still an art form and something I could never do, but unfortunately not easily automated. In America, we have a new oak, charred barrel law for all bourbon. This means we are at the true beginning of the barrels life cycle. This also means that they are the ones cutting fresh staves and getting them through to charring and testing as fast as possible. ISC has been able to automate parts of the barrel making process, but as you will see in my story below, there are some things that must always be done by hand.

I was given a walk-through of the Lebanon, KY ISC facility by Michael who works in quality control. Independent Stave Company began in 1912 and they are currently the world’s largest producers of bourbon barrels. They do work for most of the whiskey brands in North America, but Brown-Forman does have their own coopering facilities. ISC has locations globally including multiple US locations, Chili and Australia. They also make wine and tequila barrels, but the site I visited in Lebanon is specifically for bourbon. They source all of their wood from Missouri oak trees. Each tree is around 100 years old and will produce enough wood for two barrels to be made. The wood arrives to the facility in planks. The planks are then left outside somewhere on site to “season” and increase in moisture content. Each customer can determine how long “seasoning” must go on before their casks are made, but it can last anywhere from 3 months to a year. The planks are then cut again into staves. This is an important part of the process. All of the employees are paid based on quantity/pieces, but if quality is lacking the bad pieces are sent back to them. The incentives to work quickly but with high quality decides your final paycheck. There are specific rules when cutting wood down to staves. There are specifications of how large knots can be and where the knots are located.

Once the staves are cut they are sent to the next building where the assembly of the barrel begins. Assemblers are different than coopers. Assemblers are picking out the newly cut staves and setting them with temporary wire rings. A bourbon barrel must only be made of 30-32 staves. Picking the right size staves to fit correctly is the crucial part of an assembler’s job. A full bourbon barrel can hold about 53 gallons of liquid. This is much smaller than your typical sherry butt or port pipe. Once assembled with temporary metal rings, the barrel is heated and steamed to set the staves together. It is at this time that the temporary rings are tightened even further. Throughout the whole process is a series of steaming and drying to get the staves as tight as possible and prevent leaks.

The next step is charring. This is where a brand’s standards come back into play. There are multiple levels of charring. Each level means the barrel is torched/charred for a different amount of time. Most brands request a level 4 char or 55 seconds of flame. Maker’s Mark is the most widely known exception and they require a level 3 char which equals 35 seconds of flame. No one really goes below the level 3 mark. The charring is the most automated part of the process. The barrels can easily be rolled through and torched at very consistent and equal levels. It also smelled like s’mores in this part of the facility and that was great too.

After charring, the barrels are sent to the hoopers, where the final metal hoops can be set. To ensure the hoops are set as tight as possible a machine will put upwards of 1500lbs of pressure on each of the 6 hoops. The lightly toasted heads are then placed on each side of the barrel and sealed with an FDA approved glue to get as snug of a fit as possible. They will let this new barrel sit for a few days and as it continues swell. It is not ready for whiskey yet. They will drill the bung hole and then test the barrel multiple times with air and water pressure to check for leaks. This is where the coopers come into play and the déjà vu of the Speyside Cooperage visit in Scotland begins happening. If a leak is found the cooper has two choices: either the hoops are removed and the skilled cooper now has to find a new stave to replace where the leaks were or put cat tail plants in to stop the leaks. Who knew those cat tails I saw on the lakes growing up in New York would end up in Kentucky for use at the cooperage! Assessing the leaks and knowing what is the best solution is the true skill of a cooper. This is the barrels last chance to make it to a distillery for filling. This is also the bottle neck of the process, but there is no way to automate this.

I highly recommend visiting the Independent Stave Cooperage or any cooperage at that. Like many other skills in the whiskey industry, it is an art that still has not been perfected by machines and automation. You can imagine that the brands and ISC work closely together and they recently started a research and development facility. Here they are studying wood, charring and anything else that can aid in the advancement of aging whiskey.