Barrel Aged Whiskey
There are a lot of different names for moonshine. White dog, white lightning, and mountain dew are among the more popular terms used to describe homemade spirits. What do these names have in common? Well, they hint at the fact that moonshine is typically crystal clear and typically doesn't have the dark caramel color that store bought whiskey does.
The color (or lack thereof) of moonshine is confusing to a lot of people. You see, most folks think that moonshine is clear because it's made with a different process than store bought whiskey. However, that's not the case. Store bought whiskey (everything from Jim Beam Bourbon to Jameson Irish Whiskey) comes off the still as clear as mountain spring water. That's right, initially, all whiskeys look exactly like moonshine. It isn't until whiskey is aged in wooden barrels that it takes on darker colors.
Why is Whiskey Aged?
Why is whiskey aged? Well, similarly to many other longstanding traditions, the practice of barrel aging grew out of necessity. Early producers and transporters of wine used wooden barrels to ferment and then ship their products. Though, the practice has withstood the test of time because, coincidentally, long term storage in barrels has a positive effect on the character and smoothness of most alcoholic beverages. Early consumers of these beverages noticed that (typically) the longer the beverages had been stored in barrels, the better they tasted. Thus, the demand for barrel aged wine and spirits was born.
What Happens During Aging?
During the storage period changes in temperature and humidity cause alcohol to be pushed into and sometime sucked out of out of the wooden walls of aging barrels. As this natural ebb and flow occurs the alcohol is gently filtered by the wood. Some of the whiskey (typically lighter and more volatile compounds) actually evaporate through the wooden container walls (which is called the angels share). At the same time, vanillins and tannin are extracted from the wood and impart their unique flavor and color to the whiskey. The cumulative effect of the intricate process of barrel aging is a final product that has more character and less bite than the clear, fiery spirit that went into it.
How to Age Whiskey
There are two ways to age whiskey. The easiest way to accomplish aging is to add charred oak chips to a jar or bottle of spirits. The chips will naturally absorb and release spirits contained within the vessel, allowing the wood to impart its flavors to the spirit. However, this method will not allow the volatile compounds to escape by forcing their way through the container walls (as happens during traditional barrel aging). Accordingly, one must regularly open and close the vessel in order to allow trapped alcohol vapor to escape and be replaced by air. Amazon.com actually carries inexpensive, high quality, american oak aging chips.
A less involved but slightly more expensive method of DIY whiskey aging is to purchase an actual charred barrel. This method should be a bit easier to manage because evaporation of spirits and the resulting oxygenation will happen automatically. There will be no need to open an close the container to allow more volatile substances to escape. Once you have your barrel make sure to first fill it with warm water and leave it sit until the wood swells enough to prevent leaking between the staves. The hydration process could take anywhere from a few hours to a few days. It's very important that you do this to prevent your spirits from leaking out of the barrel when you initially fill it. Again, Amazon carries inexpensive, high quality wooden aging barrels.
How Long Does Barrel Aging Take?
Fantastic results can be achieved in a relatively short amount of time with home aging. This is because the surface to liquid ratio of DIY aging kits is much higher than that of commercial outfits. The commercial whiskey industry ages their product in 53 gallon barrels to achieve a better economy of scale. In a small half gallon barrel there is 4-5 times more wooden surface area in contact with the whiskey. It's less efficient from a materials standpoint (which is why commercial distilleries age in 50+ gallon barrels) but much more efficient from a time and aging standpoint. All of that extra surface area rapidly accelerates aging of the spirits. Aged perfection that takes years to achieve in 53 gallon barrels can be accomplished in a matter of months with a half gallon barrel.
The benefits of aging can be negated if too much of the wood flavor is imparted to the whiskey. "Over oaking" your spirit is a definite possibility. Every few weeks, a small sample should be drawn from the vessel to ascertain quality of aging. Once the whiskey has achieved the color and smoothness of your liking, transfer it to a glass bottle or jar for long term storage.
Here's a great summary of the barrel aging process written by the American Distilling Institute.