Explaining exactly what is behind the 12 bottles reviewed below would take me all night. So I’m going to let Buffalo Trace explain its Single Oak Project for itself:

On Friday, April 29^th, Buffalo Trace Distillery unveiled its latest endeavor to a select group of spirits writers from around the world; a line up of single tree bourbons it hopes will lead to the world’s perfect bourbon.  Officially called Single Oak Project Kentucky Straight Bourbon Whiskey, this project is an amazing mixture of creativity, patience, ingenuity and dedication.

Beginning in 1999, then Warehouse Manager Ronnie Eddins traveled to the Missouri Ozarks to hand pick 96 trees, consisting of fine grain, medium grain and coarse grain wood, based on the tree’s growth rings. Each type of grain indicates a different growth rate and will yield a different flavor profile.  From there, each tree was cut into a top and a bottom piece, yielding 192 unique sections. Next stop was the lumber yard, where staves were created from each section and were tagged and tracked. The staves were divided into two groups and given different air dried seasonings, 6 months and 12 months.  The air drying allows Mother Nature to break down some of the more harsh flavored characteristics commonly found in wood.

After all the staves were air dried, a single barrel was then created from each tree section, resulting in 192 total barrels.

The next step in the process was to experiment with different char levels of the barrels. Two different char levels were used, a number three and a number four char. (The standard char level for all Buffalo Trace products is a number four char, which is a 55 second burn.)

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

And then, the waiting began.  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!

But the best is yet to come – Buffalo Trace is asking consumers to rate each whiskey they taste online at www.singleoakproject.com and give their feedback. On the website, consumers create a profile and after rating each bottle, will then see the aging details and provenance of each barrel. They can interact with others who have also reviewed the barrel, compare their reviews on the same barrel, and even use it as a learning process for themselves by discovering which characteristics they like in a bourbon to help them select future favorites.

Participants online will earn points after reach review and most importantly, help Buffalo Trace Distillery create the perfect bourbon!

“This has been a painstaking but at the same time, fun project for us,” stated Mark Brown, president and chief executive officer of Buffalo Trace Distillery. “Even after making bourbon here for over 230 years, we still have an insatiable desire to learn, and what better way to do that than to solicit the help of some of our most loyal fans to tell us what they like, why they like it, and then set about making it!”

No matter what the results online show, Buffalo Trace will have a wealth of knowledge about key variables used in making bourbon. At the conclusion of the project the Distillery plans to take the top rated barrel, make more of that product and launch it under the Single Oak Project nameplate.

“Will this project lead us to the Holy Grail of bourbon?” Brown muses, “I don’t know. I hope so, but either way, it sure has been a great ride trying.”

The first release of the Single Oak Project Bourbon is expected to hit stores nationwide in very limited quantities around the end of May. Each release will consist of 12 unique single barrel bourbons. Every case will contain 12 bottles, each from a different barrel. The first release is made up of barrel numbers 3, 4, 35, 36, 67, 68, 99, 100, 131, 132, 163 and 164. Each of these barrels had the same entry proof, seasoning, char level and warehouse aging location. However, the  hope is to identify the differences in taste based on recipe, wood grain size and tree cut as these characteristics varied amongst this group of barrels. There will be a series of releases over the next four years until all of the 192 barrels have been released.  All releases will be packaged in a 375ml bottle. Suggested retail pricing is $46.35.

Got that? So here we have 12 bottles of Bourbon, all made with the same fill proof (125 proof), seasoning (6 months), char (#4), and warehousing (wood floor). All are eight years old. They differ by recipe (either more wheat or more rye), tree cut, and wood grain of the barrels. All are 90 proof when they hit the bottle.

And here is what we thought about all 12 of the first wave, along with information about their “DNA,” which we learned after tasting by stepping through the review process on the Single Oak Project website (a rather lengthy process if you’re sampling 12 whiskeys). If you’re sampling any of these blind, you might consider what follows to be a spoiler!

Here’s every barrel reviewed on one page

Buffalo Trace Distillery Single Oak Project Barrel #3 – Overwhelming orange notes, young. Not overly sweet, lots of bite. No real wood character. B (rye, 125 entry proof, level 6 seasoning, wood ricks, #4 char, 16 growth rings/inch, 42 staves/barrel, top half of tree)

Buffalo Trace Distillery Single Oak Project Barrel #4 – Astringent on the tongue and hugely grain-focused. The finish is medicinal, sour, and rough. One of my least favorite of the bunch. C- (rye, 125 entry proof, level 6 seasoning, wood ricks, #4 char, 16 growth rings/inch, 47 staves/barrel, bottom half of tree)

Buffalo Trace Distillery Single Oak Project Barrel #35 – Rich and creamy, with loads of caramel, coffee, dark chocolate. Wood comes along on the finish, and the whole affair offers a wonderful balance. A favorite — and a surprise; we guessed it was rye-based. A (wheat, 125 entry proof, level 6 seasoning, wood ricks, #4 char, 17 growth rings/inch, 43 staves/barrel, top half of tree)

Buffalo Trace Distillery Single Oak Project Barrel #36 – Classic Bourbon style, the long finish is smooth but serious. Lush with big caramel and vanilla notes and creamy in the mouth. A little apple pie on the finish. One of the best on the block. A- (wheat, 125 entry proof, level 6 seasoning, wood ricks, #4 char, 17 growth rings/inch, 55 staves/barrel, bottom half of tree)

Buffalo Trace Distillery Single Oak Project Barrel #67 – A bit astringent, big sweet caramel character. Not much beyond first impressions. B- (rye, 125 entry proof, level 6 seasoning, wood ricks, #4 char, 12 growth rings/inch, 33 staves/barrel, top half of tree)

Buffalo Trace Distillery Single Oak Project Barrel #68 – Super woody, but shows its charms as you drink it. Some vanilla and spice on the finish. Nothing out of the ordinary. B (rye, 125 entry proof, level 6 seasoning, wood ricks, #4 char, 12 growth rings/inch, 44 staves/barrel, bottom half of tree)

Buffalo Trace Distillery Single Oak Project Barrel #99 – Sweeter but not terribly nuanced, and not a lot of secondary character. Good, creamy body. Not a whole lot to it but an easy drinker. B+ (wheat, 125 entry proof, level 6 seasoning, wood ricks, #4 char, 12 growth rings/inch, 35 staves/barrel, top half of tree)

Buffalo Trace Distillery Single Oak Project Barrel #100 – Another easy whiskey, with a little vanilla and round mouthfeel, but not a lot of character. B (wheat, 125 entry proof, level 6 seasoning, wood ricks, #4 char, 12 growth rings/inch, 43 staves/barrel, bottom half of tree)

Buffalo Trace Distillery Single Oak Project Barrel #131 – Really woody, and far out of balance. Lots of alcohol on this one, with a tough, super woody finish. C (rye, 125 entry proof, level 6 seasoning, wood ricks, #4 char, 8 growth rings/inch, 42 staves/barrel, top half of tree)

Buffalo Trace Distillery Single Oak Project Barrel #132 – Smooth and delightful, with caramel, vanilla, and spice. Really nice body. Perhaps the favorite of the night. If this is from the top part of the tree that #131’s barrel is from, they’re night and day. A (rye, 125 entry proof, level 6 seasoning, wood ricks, #4 char, 8 growth rings/inch, 65 staves/barrel, bottom half of tree)

Buffalo Trace Distillery Single Oak Project Barrel #163 – Caramel apple character, with bit of vanilla and a somewhat thin body. Really nice flavor, but the body lacks weight. A- (wheat, 125 entry proof, level 6 seasoning, wood ricks, #4 char, 9 growth rings/inch, 60 staves/barrel, top half of tree)

Buffalo Trace Distillery Single Oak Project Barrel #164 – Amazing bite on this, astringent. A little vanilla and caramel on the palate, but the body is thin and unmemorable. B- (wheat, 125 entry proof, level 6 seasoning, wood ricks, #4 char, 9 growth rings/inch, 38 staves/barrel, bottom half of tree)

And so what did we learn from all of this?

When embarking on this tasting, we were skeptical: We figured the rye vs. wheat recipe would make a big difference between bottles — and it did — but could having a barrel cut from the top of a tree vs. the bottom of a tree, or one with a tighter wood grain (higher growth rings/inch) vs. looser grain (lower rings) make a difference? What about barrel staves? The conventional wisdom (what there is of it) holds that fewer staves equal better barrels (and better whiskey), because the wood planks used to make them are sturdier and higher quality. Narrow staves mean, in theory, that the wood is cheaper, so lots of staves in a barrel is a warning sign… or is it?

Our results were all over the map. Our easy favorite was a wonderful rye, cut from the loosest grained wood in the roundup (8 rings/inch) and with a whopping 65 staves in the barrel — the most in the roundup. If more staves equals lower quality, that didn’t pan out here.

Following that were two wheat whiskeys, one with loose grain (9 rings) and one with very tight (17 rings). Both had very narrow staves, also. While the tight-grained wheat whiskey was preferred over the looser one, both were solid.

But what of the other nine whiskeys? Seven fell into the B range but two were outright misses. Both were rye whiskeys, but none of the other data about the barrels was of much use, falling all over the map. The most notable data point: In general, adjacent barrel numbers (which seem to be from the same tree, one the top and one the bottom) had largely similar notes — but not always.

My hunch? It’s not so much the type of wood the determines the quality of the whiskey as it is the quality of the tree from which the barrel was made. Either that or it’s just dumb luck.

Fascinating stuff. Definitely something to try if you can afford several bottles for comparison.

Update: John Hansell of Malt Advocate weighs in, with similarly mixed opinions — and some different favorites.

$46 each (375ml bottle) / singleoakproject.com