5 Environmental Factors that can Affect your Whisky Cask Investment

by Aaron Damiano Sparkes
Founder of Whisky 1901

Variations in temperature, humidity, air pressure, and wood quality can ultimately affect the quality of Scotch whisky.

Here are five environmental factors to consider before you embark on your first whisky cask investment:

A view of Scotland where whisky is produced

Wood type

Much of whisky’s flavour comes directly from the cask. In fact, many experts say that as much as 75% of the spirit’s flavour is directly related to the type of cask used to mature the whisky within. This is why the crafting of a whisky cask is considered an art form in Scotland, where casks must be made from oak.

Two types of oak are used for maturing whisky: American oak (Quercus Alba) and European oak (Quercus Robur). Each has their own individual merits, but European Oak has a more robust aroma, whereas American oak is finer and subtler. Up to 90% of whisky casks in Scotland use American oak.

Maturation is the be all and end all when it comes to whisky production. The Scotch Whisky Regulations state that the spirit must mature within the cask for a minimum of three years. However, the longer the spirit remains inside the cask the more the whisky merges with the oak and develops it own unique flavours. So, if you are considering a Scotch whisky cask investment, it’s worth researching both the wood of the cask and the maturing process of the distillery you have in mind.

Humidity & temperature

The humidity within a whisky warehouse plays a vital role in the whisky maturing process. Indeed, as whisky matures in its cask, a small amount evaporates into the wood (which is porous). Usually, this evaporation is small, not more than 2% p.a., and fondly referred to as the ‘Angel’s Share’.

The higher the humidity inside the warehouse, the higher the rate of evaporation – which is typically the case of whiskey production in hot dry climates like Kentucky and Tennessee. In Scotland, however, where temperatures are moderate, it is generally said that the lower humidity allows the whisky to mature faster, which has a direct correlation with the whisky’s strength.

Many experts think the ideal temperature in a warehouse should be between 10-18°C. With that said, whisky will simply not mature if the temperature is too cold, whereas too high a temperature would lead to the Angel’s Share becoming more of a gulp than a gentle sip. Direct sunlight is also avoided, as are erratic fluctuations in temperature.

Intriguingly, the exact influence of humidity and temperature on the maturation process is still not fully understood and technical research is ongoing. But one thing is certain: Scottish distilleries having been making whisky for generations and are famed for their knowledge and expertise.

By choosing one of our many prestigious distilleries that we partner with, your whisky cask investment will be in the safe hands of Master Distillers and Master Blenders who are committed to producing the finest whiskies in the world.


The Scotch Whisky industry is heavily dependent on regular sources of freshwater for the various stages of whisky production – from malting and mashing to distillation and dilution.

Whisky, of course, is an extremely water-intensive commodity and the water that comes from streams, lochs, groundwater, or piped-in supply goes a long way to influencing the finished product. The UK’s Waste Resources & Action Programme estimates that around 61 billion litres of water are used by the industry each year – the equivalent of 47 litres for every litre of Scotch produced.

With this in mind, the canny investor may want to look at the rainfall patterns of recent years before deciding on their whisky cask investment. For example, in the summer of 2018, one distillery in Speyside reported an entire loss of production for a month due to draught conditions, amounting to 300,000 litres of whisky.

Air flow

Like temperature and humidity, the flow of oxygen throughout a warehouse is another crucial factor when it comes to evaporation rates and the maturation process.

The purpose of good air ventilation is to dissipate the air which has become laden with alcohol vapours (having evaporated from the whisky casks). However, the type and design of a warehouse should also be considered, and it is worth your time to find out how your whisky cask investment is being stored.

For instance, a traditional dunnage warehouse stacks up to three whisky barrels on top of each other and is typically built with stone walls. In contrast, a racked warehouse is made from brick or concrete and stacks eight-to-12 whisky barrels on racks with metal shelves.

Dunnage warehouses are lower and smaller, and the air enters and exits through windows at each end. In racked warehouses (which are windowless), air flow enters through vents in the floor and exits through vents in the roof.


One of the key reasons why Scotland is the ideal location for whisky production is its abundance of different microclimates, from the Highlands to the Lowlands. In fact, on occasions it is not unusual for Scotland to experience four seasons in one day. But this is a key advantage, and it explains the staggering variety of Scotch whisky produced each year.

Of course, the location of a distillery will directly influence the flavour of whisky, which in turn is related to the locality’s climate. As mentioned earlier, long-term whisky cask investors may want to examine the effects of climate change on the Scotch whisky industry in the coming years.

Future climate change projections indicate that Scotland will increasingly experience warmer summers and wetter winters, leading to challenges of water supply in certain areas. However, the industry is already looking closely at diversifying its production processes in order to preserve the character and quality of Scotch whisky.

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