Casks of scotch whisky have to be matured in a bonded warehouse in Scotland, and they will stay there until you decide to sell your cask. However, whisky casks are active vessels experiencing evaporation and changes in alcoholic strength, and while some people do just forget about a cask for thirty years, it is much better practice to monitor how your whisky is progressing. A whisky cask “health check” is done through regular regauges.
Why Do A Health Check?
When whisky is maturing in a cask some of the liquid will evaporate. This is because casks are made from wood, which is porous. In Scotland the alcohol in the whisky evaporates more readily than the water, which means that the ABV (alcohol by volume) of your cask drops as well as the liquid volume.
The evaporation of liquid and alcohol is called “the angel’s share.” It is important to monitor because you do not want all the whisky in your cask to be gone when you come to sell it. Also the Scotch Whisky Association states that whisky must be at 40% ABV or higher to be legally classified as scotch whisky. If the ABV of your cask drops below 40% the cask is essentially worthless. This means that while evaporation is a natural part of cask maturation, monitoring it through health checks can help you understand the value of your cask and help you decide when to sell.
Send Me The 2026 Cask Buying Guide
Our Cask Buying Guide was the first independent guide written for private buyers and remains the most comprehensive available. No sales pitch or inflated promises, just clear, practical guidance on ownership, pricing, risks and what to check before you buy
"*" indicates required fields
Evaporation also means that casks have a finite lifetime, which means they have to be bottled at some point. Generally a cask’s lifetime is considered to be under 50 years, which currently makes it a wasting asset, and exempt from capital gains tax.
What Is A Regauge?
A regauge is the industry standard way of monitoring the health whisky casks. A regauge measures the total volume of liquid in the cask (bulk litres) and the alcoholic strength (ABV) of the liquid your cask. There are two types of regauge: discharge and dip. A dip regauge is the most common for monitoring a cask within its lifetime as it is the least intrusive.
Keeping an eye on the health of your cask is essential to having a profitable experience, so always make sure that you are conducting regular regauges on your cask. For private individuals we suggest regauging every three to five years. This frequency range gives a good indication of how a cask is maturing without disturbing it too often.
We are always happy to answer questions about casks, so if you have a question about a cask you own or are looking to buy please feel free to get in touch.
