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Angel’s Share- An Inevitable Loss; But we might be able to prevent it

Imagine you have opened up your own distillery for the production of whisky. Since you are an intelligent distiller, you know that one of the crucial stages of producing whisky is ageing it in oak barrels. But wait! You start noticing something fishy happening in your distillery. The whisky kept in the oak barrels for the purpose of maturation starts disappearing with time! No, there’s no leakage in the barrels, nor there was any theft in your distillery. The lost whisky remains a mystery. You start getting tensed as the amount of lost whisky takes a toll. The coworkers start questioning your intelligence. And your customers…errrr…they start cursing you. They curse you because you sell them your whisky at an expensive rate. But what other option have you got? None. You have to pay for the production of all that lost whisky after all. So,  you need to charge your customers for it if you ever want to make any profit. Fear crept into your mind that this will make you lose your customers. But my friend, your customers won’t dwindle in number! Because it’s not just you who is losing his precious volumes of whisky. Literally, every distillery in the world has to face this loss. The whisky is not actually lost magically. The barrel in which you were maturing may not have leakages on its surface but it indeed has several microscopic pores in it. Your whisky moved outwards through these pores and evaporated which decreased the amount present inside the barrel.

As a matter of fact, this loss used to take place in the whisky distilleries of the distant past as well. Just like you, the distillers of that time were intelligent too, but even they failed to understand the mystery behind their disappearing whisky. They simply put the blame on the heavenly angles. According to them, the angles would take away a part of the whisky as a form of tax for ageing it. The evaporated whisky has since been infamous by the name of Angel’s share.

So how bad is this Angel’s share?

Well, first of all, it’s not all bad. To understand why you just need to take a sip of a fresh whisky that has not matured yet. You will immediately find yourself spitting it out due to its awful taste. The awful taste is due to its high alcohol content (as high as 190 proof). Angel’s share puts this alcohol content down and makes the whisky milder. Not just this, the evaporated whisky moves up and feeds the black fungus, Baudoinia Compniacensis, which resides in the rafters and ceilings of maturation warehouses. This fungus is consumed as food by the local insects which are further ingested by spiders which keep other boring bugs off the barrels containing whisky.

Angel’s share could have been a good thing only but one just can’t ignore the irrefutable loss of the whisky volume. For Scottish whisky, it leads to a 2% average loss in volume per year. Sounds small? Well, according to, the total amount of maturing whisky in Scotland is approximately 250 litres at any time. Taking 2% of it, we can say that 29 million gallons of Scotch are lost each year due to Angel’s share, enough to fill up 44 Olympic swimming pools. The loss is as high as 12% in India. 

Factors affecting Angel’s share : 

There are many. In fact, even moving a whisky cask could increase Angel’s share by 1-2%. The important factors are mentioned below :

  • Climate: Higher the climate, higher the evaporation and hence, higher the Angel’s share. For instance, Kentucky has a much hotter climate than Scotland. It would take a barrel three years in Scotland to equate the amount of whisky lost in one year in Kentucky. 
  • Humidity : If the atmosphere has more humidity, alcohol in the cask evaporates faster than water and it’s concentration increases. On the other hand, if humidity is low then water evaporates faster and the alcohol concentration decreases.
  • Barrel size : Whisky in smaller barrels are in a greater contact with the container. Therefore, the evaporation is also more in case of smaller barrels.
  • Air flow : More room around the barrels to flow, the higher the Angel’s share. In bigger warehouses, the casks are stored at a slight greater height from the ground in racks or pallets.  Air circulates around them leading to greater Angel’s share.

How to prevent it?

For several years,  distillers could do nothing but just watch their precious whisky disappear into thin air. But today, we have several ideas for decreasing this Angel’s share, though this is still a field that needs much further progress. One of the initial ideas was to cover the casks with polythene which won’t let the whisky escape. At a first glance, this sounds great. But if carried out in real, the casks won’t be able to breathe. The oxygen in the air moves into the barrel through its surface pores and causes the breakdown of some undesirable compounds in the whisky which makes the whisky milder in taste. So it’s not a good idea at all. A new device called ‘ Scotch Bonnet’ has been introduced by a firm, Sangobeg Ltd. Its developers claim it to reduce Angel’s share through the barrel tops without affecting the whisky.

The device is meant to be fitted on the top of the whisky cask and then attaches itself to one of the hoops on the cask. Moreover, it is a durable and reusable device. Other than that, temperature and humidity control methods may also be used in the warehouses to reduce Angel’s share. In fact, a system has already been developed to serve such a purpose. It is called the Airtec® EasyLine™ humidification system which together with a reverse osmosis water system stabilizes the humidity in the storage area. The system consists of an EasyLine™ pump station with two control zones, two HydroOnes™and two HydroFlex™. A special kind of barrel has also been developed by a team of scientists at Edinburgh Napier University that reduces Angel’s share. They have even received the Queen’s Anniversary Prize for their research in 2015. 

But still, it will probably take quite some time for every distillery in the world to get it’s a reliable way of beating off the loss in whisky due to evaporation. Till then, the Angel’s are pretty much free to enjoy their share!

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