What is The Angel’s Share? What We Know About This Boozy Phenomenon
The Archangel Gabriel by Masolino da Panicale. (Photo: National Gallery of Art)
What is the angel’s share? This ethereal phrase is often uttered by distillers and whiskey brands. The mysterious phenomenon is an integral part of the distillation process.
Yet, for many, there is still a lot of confusion surrounding what the angel’s share actually is, its origin story and some of the devilish side effects of an increase of angel’s share as we experience a global whiskey boom.
Without further ado, we’re going to spend some time doing a deep dive on the angel’s share — no halos required.
What Is The Angel’s Share?
The angel’s share is a byproduct of the whiskey maturation process. (Photo: AP Photo/The Casper Star-Tribune, Alan Rogers)
Angel’s share is a phrase that is most commonly used in whiskey production. It is what happens when a combination of water and a maturing spirit is lost to evaporation. During the maturation process, both water and alcohol end up evaporating as typically, the spirit is aged in porous wooden barrels.
Distillers often fill casks up partially, because when alcohol gets hot it tends to take up more space, which in scientific terms is a process called thermal expansion, according to Encyclopedia Britannica. A common example of thermal expansion is when alcohol levels rise within a thermometer.
The same process takes place in barrel aging whiskey, and distillers take that into consideration during the maturation process because they don’t want to lose their whiskey as it seeps through the pores of their barrels. Instead, whiskey is lost during the aging process in a completely different way: enter angel’s share.
As the oxygen interacts with the wood, and barrels are subjected to temperature changes, they expand and contract. When the wood is subjected to different factors like heat and humidity, a portion of alcoholic vapors evaporate. Now, when Scottish and Irish distillers were making whiskey in the middle ages, they had no idea about thermal expansion and evaporation. So, distillers assumed the missing liquid was enjoyed by greedy, whiskey-loving angels.
What Influences the Amount of Angel’s Share?
Sometimes, the type of oak used in aging a whiskey can influence the amount of angel’s share. (AP Photo/Mike Groll)
The typical amount of loss due to the angel’s share can range depending on a variety of factors. In some places, 2% is lost to the angels each year. In other locations, let’s just say the angels are a little thirstier, and the rates can be as high as 6%. But why is that?
A lot of factors influence the amount of alcohol that evaporates from the barrel. Climate is one factor, and in hotter environments, more alcohol gets sucked up into the ether from evaporation.
Humidity is another factor that influences the evaporation of water within the angel’s share. If a warehouse has a high level of humidity, according to Whisky Magazine, less water will evaporate from the barrel. Yet, if a warehouse is in a dry climate, more water will evaporate from the cask, yielding a spirit with a higher level of alcohol.
Elevation has an impact, too. Locations at higher altitudes tend to experience higher levels of angel’s share thanks to lower vapor pressure and humidity, which allows alcohol to evaporate more than lower-altitude areas.
There are other factors to consider beyond environment in terms of how much angel’s share evaporates from the barrel. The type of oak used can also influence the amount of watery, alcoholic vapors lost to evaporation. According to Whisky Magazine, American Oak is typically tighter, whereas certain species of European oak might be more porous, allowing for more evaporation to take place.
The age of a whiskey is also important to consider, as the longer the spirit spends in the barrel, the more likely a steady rate of it will be lost to the angel’s share. This is often one of the reasons why older whiskey is more expensive.
Whiskey Fungus: A Devilish Side Effect of Angel’s Share
Whiskey fungus feeds off of ethanol vapors from the angel’s share. (Photo: AP Photo/John Amis)
As whiskey production booms, a phenomenon has started to become more prevalent in the environments surrounding distilleries. Many residents neighboring barrel warehouses have described an ashy, pencil-shaving-like substance covering their homes and the surrounding areas. This substance is called baudoinia compniacensis, or whiskey fungus.
Though whiskey fungus has been around forever, a recent production boom has led to more extensive outbreaks of the black substance, and the reason? Angel’s share. Baudoinia feeds off of the ethanol vapors that escape barrels thanks to the angel’s share, and a heat-shock protein from the vapors makes this particularly nasty little fungus very difficult to get rid of.
Major spirits brands like Diageo, WhistlePig and Jack Daniel’s have faced lawsuits from their neighbors over baudoinia outbreaks. Though as of now, the fungus is not known to cause any harm to health, it’s clearly problematic for residents as many have to pay cleaning fees to rid their property of the black, sticky substance.
As the bourbon and whiskey boom continues and more angel’s share appears as a byproduct of the maturation process, we may see more outbreaks of baudoinia in the future.
Angel’s Share: Not Just a Whiskey Phenomenon
Angel’s share occurs during the production process of other spirits as well. Tequila, for example, experiences losses due to angel’s share, as do rum, cognac and even wine! Basically, any alcohol that ages in wooden barrels. Yet, this term is typically used in whiskey production.
Many distillers to this day believe in the charming myth about angel’s share and claim these losses are a noble gift to the heavens, ensuring their whiskey comes out of the barrel tasting exceptional.
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