American Bourbon By Jonathan Houston / April 20, 2016 Share Tweet Share Share Editor’s Note: We’ve just launched sign ups for our upcoming The Whiskey Wash newsletter. Click here to join our list and stay informed! When talking about whiskey, there are certain terms that come to mind: full-bodied, smooth, robust. However, there is one phrase that affects every single batch of whiskey made: angel’s share. While this term may not be found on the side of a bottle, it is something that pervades the whiskey industry. But what does it mean? To understand it, we must first understand the process by which whiskey is made. These days, pretty much all whiskeys are aged in wooden barrels. The wood absorbs some of the more unpleasant aspects of distillate (such as sulfur), and, in return, imbues the liquid with flavors unique to itself. The harmony between whiskey and wood has existed for years. However, there is a catch; due to the porousness of the barrel, some of the liquor inside would disappear during the critical aging process. The result? A loss of about 2% of the total volume per year. Because the liquid would evaporate into the heavens, it was dubbed the “angel’s share.” Images of drunken angels notwithstanding, this unavoidable circumstance is both a blessing and a curse. As we mentioned, one of the biggest reasons alcohols like whiskey are aged in barrels is to remove some of the undesirable parts of it. The “angel’s share” phenomenon further helps with the maturation and smoothness of the liquid, as it can reduce an almost undrinkable, high-proof moonshine into a soft, clean-finished whiskey. Buffalo Trace barrels patiently maturing – and losing angel’s share all the while. (image via Buffalo Trace) However, the downside of this is that, since most whiskeys and scotches are aged for many years, the total volume can drop quite significantly. For example, a twelve-year-old scotch can lose up to 24% of its liquid by the time it’s ready for consumption. This is further exacerbated in warmer, drier climates where the angel’s share can be much higher, reaching upwards of 4-5% per year. Thus, a whiskey produced in the fields of Kentucky can be affected far more than a scotch made in the Scottish highlands. Another effect on the alcohol content of batches of whiskey is the relative humidity. In many cases, the proof of the whiskey is reduced as alcohol evaporates. In low humidity climates, however, more water will evaporate than alcohol, increasing the overall proof. Simply put, depending on where the whiskey is produced, the angel’s share will have a different effect on it. So are we to rob the angels of their sweet, sweet drinking habit? Is there a way to reduce the alcohol content without removing too much of the liquid itself? Diageo seems to have found a solution to the “problem.” Their answer? Plastic wrap. By coating the outside of the barrel in this film, it seems to eliminate the evaporation problem – much to the chagrin of all the angels, we’re sure. However, whether or not it leads to a higher alcohol content is yet to be determined, as the company is still playing around with the results. So, whenever it may come to pass that you leave this mortal coil, just be content in knowing that, for the time being, at least, you can still enjoy your favorite drink in heaven (just be willing to share).