Barrel stave seasoning and barrel char levels are the latest variables Buffalo Trace Distillery attempts to examine with the release of its fourteenth round of the Single Oak Project Bourbon. This August 5, 2014 release features bourbons which were all aged in barrels made from the bottom half of the tree, while keeping the other variables such as entry proof (at 125), and warehouse type (all aged in Warehouse K, a wooden floor warehouse) the same. The remaining variables, recipe (wheat or rye), grain size, barrel stave seasoning, and char level vary.

To further explore the results of using different char levels and stave seasoning, Buffalo Trace turned to barrel expert Brad Boswell, president of Independent Stave Company, the cooperage Buffalo Trace partnered with on the Single Oak Project. “Charring the wood breaks it down quickly and certainly changes the flavor, in a more intensive way than just seasoning. Charring provides more of the vanilla and caramel characters coming from the barrel.

A number three char (which is what Buffalo Trace used on some of the barrels in this release) takes approximately 45 seconds while a number four char (the other char level Buffalo Trace used on the barrels in this release) takes approximately 55 seconds. The lighter char preserves more of the natural oak aroma and flavor (think a little spicy, a little earthy, with a touch of cedar). The heavier char provides more color and caramelization. Tannins will vary between these two types of barrels. The heavier char can also provide for more of a sweet smoke note that is often desired.” said Boswell.

“Stave seasoning allows the wood to slowly break down (degrade) whereas charring and toasting breaks down the wood much more quickly. When the wood air seasons, the microbial activity breaks the wood down and the rain leaches out some of the tannins. The freezing and thawing breaks down the wood. Even the UV light breaks down the wood to some extent. The flavor of the wood changes as it breaks down.

Barrels with extended air seasoning with charring will provide a slightly different array of flavors as compared to barrels with less air seasoning and then similarly charred. The levels of smokiness, vanillin, caramelization, and tannin will vary between the two types of barrels,” continued Boswell.

If past online votes are any indication, fans prefer a lighter #3 char with a six month barrel stave seasoning, as barrel #82 remains in the lead for the past several months in a row. Barrel #83 is right behind it though, with a darker, #4, char and also a six month stave seasoning.

Reviews are still being encouraged, as two more releases will take place before this project ends in the summer of 2015. More than 4,000 reviews have been given so far on www.singleoakproject.com.

The Single Oak Project is part of an intensive research project Buffalo Trace Distillery started conducting in 1999 by hand picking 96 trees with different wood grains and then dividing them into a top and bottom piece, yielding 192 unique sections. From there, staves were created from each section and were air dried for either 6 months or 12 months. After all the staves were air dried, a single barrel was created from each tree section, resulting in 192 total barrels. These barrels were given either a number three or a number four char and then filled with either wheat or rye recipe bourbon.

To further the variety of experiments, the barrels were filled at two different proofs, 105 and 125 proof. And if this wasn’t enough, two completely different warehouses were used, one with wooden floors and one with concrete floors. In total, seven different variables were employed in Buffalo Trace’s ultimate experiment.

For eight years the Distillery continued with its tracking process, creating intricate databases and coming up with a potential of 1,396 tasting combinations from these 192 barrels!

The Single Oak Project Bourbon is being released in a series every three months from 2011 through 2015 until all of the 192 barrels have been released. The first release hit select stores in 2011. This fourteenth release will reach stores towards the end of August. Like all the other releases, the quantities are very limited. Every case will contain 12 bottles, each from a different barrel. The fourteenth release is made up of barrel numbers 2, 12, 34, 44, 66, 76, 98, 108, 130, 140, 162, and 172. All releases will be packaged in a 375ml bottle. Suggested retail pricing per bottle is $46.35.

At the conclusion of the Single Oak Project, the Distillery plans to take the top rated Single Oak Project Bourbon and make more just like it, under the Single Oak name.