From the Distiller...Barrels, Barrels Everywhere
As we approach the two-year mark on our first set of whiskeys we have taken it upon ourselves to really get serious about evaluating each barrel as it matures. The number one lesson we’ve learned so far? Every single barrel is different! We put the same batch of distillate into 3-4 different barrels, yet each barrel has its own unique taste. We find this is evident at as early as 6month of age. Actually, I might even go so far as to say that the differences are more noticeable when they are this young, as opposed to after 18 months of aging. This is important to us as it gives us a chance to plan earlier what the fate of a specific barrel will be.
So why does each barrel taste different? Well, lots of reasons. We have barrels from several different cooperages, so that can explain some of the difference, but even when comparing barrels from the same cooperage they are still different. When barrels are made, the wood on the inside of the barrel is charred, which introduces differences because not every barrel chars exactly the same way. We also have a mix of barrels made from American oak, as well as some made with French oak. This is the easiest difference to taste. The French oak’s effects on the whiskey inside is a little more subtle, while the American oak tends to provide the loads of vanilla that one typically associates with a classic bourbon.
So what else gives rise to the variation between barrels? Every oak tree is a unique, and where the tree grow--its climate and environment-- all impact the wood it produces. Does every strawberry you eat taste exactly the same? Of course not, but there is a definite flavor profile associated with strawberries. The same is true for the oak trees used to make barrels. Therefore, right off the bat (er, barrel?) every tree is going to have its own unique nuances that it brings to the general oak flavor profile. That is just the start. How the wood is handled once the tree is cut down also has a big impact on flavor. The wood is first cut into stave blanks and then it is “seasoned” , i.e. it is (usually) allowed to age outside in the elements for at least 2 years before it is then given its final shape and used to make a barrel. Recently it has become common to age the wood for just six months and then kiln dry it in order to get it to a stable moisture content for consistent barrel-making properties. How does this difference between the two drying methods impact the whiskey? This actually has a pretty big impact. During the two years the stave blanks spend outside the wood actually starts to break down just a little bit and there is a little bit of microscopic fungal growth there as well. This leads to a reduction of tannins in the wood and makes it easier for flavors to be extracted from the wood and imparted on the whiskey. The longer the aging, the lower the level of extractable tannins. If the tannin levels are high, this can lead to the production of a lot of flavors that taste like, well, wood, rather than the vanilla and caramel (and smoky) flavors that we are interested in developing. Wine makers won’t even consider using barrels made with wood seasoned for less than two years – too many tannins, which will leave the wine chalky and out of balance, and ultimately will require a longer aging time in order to soften those tannins. Since whiskey stands up better to tannins than wine, it is more common for whiskey to go into barrels made from kiln- dried wood. The big whiskey producers don’t reveal exactly what they are doing, but I am very suspicious that their top-level stuff goes into barrels made with well-seasoned wood.
So let us toast (er, char) the barrel, as, at least for American whiskies, it provides over half of the flavors found in the finished product.